https://orcid.org/0000-0002-4254-4140
Figures
Abstract
Frankincense (Boswellia spp.) oleogum resin is a valuable natural source of bioactive phytoconstituents with diverse therapeutic potential. In this study, the hydrodistilled essential oil (EO) and n-hexane extract (HE) of Boswellia serrata gums were analyzed through gas chromatography–mass spectrometry (GC-MS) to determine their phytochemical composition. The GC-MS results in the identification of 62 and 71 components in the EO and HE, respectively. Acetic acid octyl ester (41.09%) and nerolidol (13.64%), were the major components of the EO. Meanwhile, incensole (28.56%), (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol (13.54%), and 24-norursa-3,12-diene (9.25%) in the HE. Regarding the antioxidant effects, the EO exhibited significantly higher antioxidant capacity compared to the HE (DPPH: 9.24 and 6.50 mg TE/g; ABTS: 25.71 and 4.94 mg TE/g), respectively. Moreover, the EO was more potent in the CUPRAC test (61.12 mg TE/g for the essential oil and 50.62 mg TE/g for HE), while the n-hexane extract (72.68 mg TE/g) showed stronger ability than the EO (13.22 mg TE/g) in the FRAP assay. The EO had a higher ability in phosphomolybdenum and metal chelation tests in comparison with the HE extracts. Further, the oil showed more potent inhibitory activity against cholinesterase, α-glucosidase, and tyrosinase than the HE extract. The HE extract was only more active on α-amylase compared to the oil. These findings suggest that olibanum EO possesses potent bioactive compounds that may contribute to the management of oxidative stress and age-related conditions, including Alzheimer’s disease, diabetes mellitus, and skin hyperpigmentation.
Citation: El-Nashar HAS, Elhawary EA, Nilofar N, El Hassab MA, Majrashi TA, Eldehna W, et al. (2026) Comparative metabolic profiling, enzyme inhibitory activities, and in-silico analysis of the hexane extract and the hydrodistilled oil of Boswellia serrata. PLoS One 21(5): e0348178. https://doi.org/10.1371/journal.pone.0348178
Editor: Phalisteen Sultan, Council of Scientific & Industrial Research Indian Institute of Integrative Medicine, INDIA
Received: February 16, 2025; Accepted: April 10, 2026; Published: May 8, 2026
Copyright: © 2026 El-Nashar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All the data contained in the manuscript.
Funding: Deanship of Research and Graduate Studies at King Khalid University for funding this work through small group research under grant number (RGP1/121/45). The majority of practical work was achieved in Egypt. ’The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: No competing interest present.
1. Introduction
In recent years, plant-derived materials have attracted much consideration and interest [1–5]. Valuable plant phytoconstituents have become advantageous when used to obtain a variety of promising biological effects [6].
The Boswellia genus encompasses about 20 species present in dry climates from West Africa, Arabia, to Tanzania. Additionally, Madagascar and India include some species. The genus is endemic in Africa (75% of the species) in the northeast regions.
Boswellia plants, Burseraceae, represent a rich source of plant phytoconstituents. Boswellia serrata is a famous species and is known as Frankincense or olibanum (In Arabic: Liban Dakar) [7,8]. Boswellia serrata is predominantly present in India, thriving in the Madhya Pradesh forests, Rajasthan, Gujarat, Assam, Bihar, and Odisha. Historically, various old civilizations, including the Persians, the Chinese, and those from early American societies, utilized olibanum for medicinal purposes.
The plant is a deciduous tree that is popular due to its oleogum resin, which carries a lot of beneficial effects in many diseases. This resinous material can be easily extracted by non-polar solvents as hexane and petroleum ether. The oleogum resin has been found to have beneficial effects on many diseases, such as asthma, bronchitis, cough, dysentery, diarrhea, cardiovascular diseases, boils, ringworms, fevers, mouth sores, skin diseases, and vaginal secretions. The volatile components identified in the resin include geraniol, eleneol, cadinene, β-pinene, linalool, phenols, bornyl acetate, terpenyl acetate, serratol, α/β-amyrin, and boswellic acid. Icensole is the main key ingredient from the hydrodistilled oil and hexane extract of the oleogum resin, with a quantity reaching 75% [7–9]. It was found to exhibit a plethora of in vitro biological activities like antimicrobial activity [10], anticancer activity [11], antioxidant activity [12], anti-inflammatory activity [13], antioxidant [14], and antimutagenic [15]. In addition, it showed different in vivo activities including anti-Alzheimer’s disease [16–20], anti-Parkinson’s disease [21], antioxidant, immunomodulatory [22], anti-inflammatory [23], anticancer [24,25], analgesic [26], smooth muscle relaxant [26], antarthritic [27], diuretic [28], antidiarrheal [29], antiasthma [30] and anti-colitis [31].
Antioxidant activity of certain plants is usually attributed to their flavonoid and phenolic contents in addition to the presence of abundant oxygenated hydrocarbons in their essential oils or non-polar extracts using petroleum ether or n-hexane. The ability of certain plant extracts or volatile components to inhibit certain key biological enzymes, such as acetylcholinesterase, butylcholinesterase, α-glucosidase, and α-amylase, is of valuable medical importance [32–34]. Thus, this study was designed to perform a comparative study between the oil and hexane extract of Boswellia serrata gums via GC/MS chemical analysis, besides investigation of the antioxidant properties and inhibitory effect against the above-mentioned enzymes participating in skin hyperpigmentation, Alzheimer’s, diabetes mellitus.
2. Materials and methods
2.1 Plant material, essential oil isolation and extract preparation
The gums of Boswellia serrata (Burseraceae) were obtained in February 2023 from the local market, Cairo Governorate, Egypt. It was deposited as a voucher specimen (PHG-P-BS-479), at the Pharmacognosy Department, School of Pharmacy (Ain Shams University), Cairo, Egypt. The Clevenger apparatus was used for hydrodistillation of 500g of the gums (5 hrs.). The oil was preserved at −4ºC for the chemical and biological assessments.
About 200g of B. serrata gums were soaked in n-hexane (2L) for three days, and the extraction was repeated 3 times. The extract was completely evaporated by vacuum at 45 °C to yield 6.30 g. The obtained extract was kept and stored at −4ºC.
2.2 Gas Chromatography/Mass Spectrometry (GC/MS) analysis
The GC/MS analysis of the oil and n-hexane extract from the gums was conducted using a Shimadzu GC-MS-QP 2010 (Kyoto, Japan). The TRACE GC Ultra Gas Chromatograph is manufactured by Thermo Scientific Corporation, USA, equipped with a thermo-mass detector at the pharmacognosy department, Ain Shams University, Cairo, Egypt. The GC/MS system utilized a high-performance TG-5MS capillary column from Restek, USA, measuring 30 m in length and 0.25 mm in diameter, with a precise 0.25 μm film thickness, ensuring exceptional sensitivity and resolution. The capillary column was linked directly to a quadrupole mass spectrometer (SSQ 7000; Thermo-Finnigan). For the analysis, a 1% v/v diluted sample (1 µL injection volume) was used, with helium as the carrier gas at a steady. The rate of flow is established at 1.0 mL/min and 1:15 as a split ratio. The oven temperature begins at 80°C for 2 minutes (isothermal), then increases at a rate of 5.0°C per minute until it reaches 300°C (programmed). This temperature is held for an additional 5 minutes (isothermal). The temperatures of both the injector and detector were kept at 280°C. The mass spectra were obtained with the following settings: interface temperature at 280°C, ion source temperature at 200°C, and electron ionization (EI) mode at 70 eV, using a scan spectral range from m/z 35–500. The relative proportions of the n-hexane extract constituents were expressed as percentages based on peak area normalization.
2.3 GC/MS identification of chemical components of the hydrodistilled oil and the n-hexane extract of Boswellia serrata gums
The volatile compounds were initially identified by comparing their spectra of GCMS, patterns of fragmentation, and Kovats indices with the NIST and Wiley libraries, as well as existing literature. [35–41]. The retention indices were calculated using a series of homologous n-alkanes ranging from C8 to C28. that were injected under the same conditions. The percentage of the peak area of each compound was determined relative to the percentage of the total area of the entire chromatogram of FID (100%).
2.4 Antioxidant and enzyme inhibitory assays
To evaluate essential oil and hexane antioxidant activity, six different spectrophotometric tests were carried out. They are the ABTS (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays, which assess the ability of antioxidants to neutralize free radicals. The reduction activity of the extract was evaluated by FRAP, the Ferric Reducing Ability of Plasma and CUPRAC, and Cupric Ion Reducing Antioxidant Capacity tests. Additionally, the Phosphomolybdenum and Ferrozine assays measured the total antioxidant capacity and metal chelating potential, respectively. Except for Metal-chelating Activity (MCA), each assay was evaluated using a Trolox standard, while MCA was compared using ethylenediamine tetraacetic acid (EDTA) equivalents per gram of essential oil/extract. Detailed steps can be found in our former works [42,43]. To evaluate the inhibitory potential of the extracts on different enzymes, we conducted assays for AChE, BChE, tyrosinase, amylase, and β-glucosidase. Experimental procedures are available in our earlier publications [42,44]. AChE and BChE inhibition were measured as mg of galanthamine equivalents (GALAE)/g of hydrodistilled oil or extract. Tyrosinase inhibition was expressed in mg of kojic acid equivalents (KAE)/g of hydrodistilled oil/extract, and α-amylase inhibition was quantified in mmol of acarbose equivalents (ACAE) per g of essential oil/extract.
2.5 In silico molecular docking study
The X-ray 3D structures of NADPH oxidase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase were obtained from the Protein Data Bank with the following IDs: 2cdu (resolution 1.80 Å), 6esj (resolution 2.98 Å), 5m8q (resolution 2.85 Å), 4gqq (resolution 1.35 Å), and 3wy2 (resolution 1.47 Å), respectively. Vina Autodock and MGL tools were used to perform the docking studies [45,46]. The major components of the essential oil, acetic acid octyl ester, nerolidol, and caprylic alcohol, alongside the n-hexane, extracted major components, incensole, (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol, and 24-norursa-3,12-diene were implemented in the docking study. All five receptors and the six compounds were converted to pdbqt format using MGL tools, as required by Vina Autodock®. The active site of each target was identified based on the binding of the respective co-crystallized ligand, with the following dimensions 22*22*22 Å in the x, y and z directions. The docking results were then analyzed using the Discovery Studio visualizer, which also generated 2D interaction diagrams.
3. Results
3.1 Identification of metabolites through GC/MS analysis of Boswellia serrata gums
The results of the analysis of both the essential oil and the n-hexane extract from Boswellia serrata gums are provided in Fig 1 and Table 1. The GC/MS investigation results in the identification of 62 and 71 compounds in oil and extract, respectively. The identified compounds accounted for 98.32% and 99.20% of the oil and extract, respectively. The hydrodistilled oil has been predominated by fatty acid methyl esters (FAMEs; 44.13%), followed by oxygenated sesquiterpenes (13.79%), diterpenes (10.18%), oxygenated diterpenes (8.81%), hydrocarbon monoterpenes (8.15%) and oxygenated monoterpene (6.01%) as represented in Fig 2A. While the n-hexane extract elicited oxygenated diterpenes as the major class of compounds followed by the oxygenated monoterpenes and oxygenated sesquiterpenes (Fig 2B).
In the essential oil, Acetic acid octyl ester (41.09%) and nerolidol (13.64%) showed the highest dominance, followed by caprylic alcohol (6.64%), kaur-16-ene (5.11%), incensole (4.72%), α-pinene (4.41%), and cembrene A (4.14%). Regarding the n-hexane extract, the most abundant volatile components were incensole (28.56%), (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol (13.54%), 24-norursa-3,12-diene (9.25%), verticilla-4(20),7,11-triene (5.79%), 24-norursa-3,12-dien-11-one (5.55%), thunbergene (4.53%), cembrenol (3.38%), acetic acid octyl ester (3.16%) and cembrene A (3.15%). As abovementioned, the oxygenated diterpenoids were the most abundant class of volatile components identified from B. serrata. Oxygenated diterpenoids came first with incensole (28.56%) and cembrenol (3.38%) as the main components identified from this class. Moreover, oxygenated monoterpenoids showed the second most identified class with their main compounds such as trans-pinocarveol (0.30%) and dehydro-linalool (0.17%). The third most abundant class was the oxygenated sesquiterpenes, which were mainly represented by nerolidol (2.22%) and viridiflorol (0.37%). The major compound structures detected in the hydrodistilled oil and n-hexane extract of Boswellia serrata gums are cumulatively shown in Fig 3
3.2 Antioxidant activity of the essential oil and the n-hexane extract of Olibanum
The antioxidant characteristics of the volatile oil and n-hexane extract were evaluated using various assays, including reducing power (FRAP and CUPRAC), radical quenching (ABTS and DPPH), metal chelation, and phosphomolybdenum. The results are presented in Table 2. In both radical scavenging assays, the essential oil (DPPH: 9.24 mg TE/g; ABTS: 25.71 mg TE/g) exhibited higher activity than the n-hexane extract (DPPH: 6.50 mg TE/g; ABTS: 4.94 mg TE/g). Furthermore, the essential oil (61.12 mg TE/g) showed greater performance in the CUPRAC assay compared to the n-hexane extract (50.62 mg TE/g), while the n-hexane extract (72.68 mg TE/g) demonstrated a stronger ability than the essential oil (13.22 mg TE/g) in the FRAP assay. The essential oil also had a higher ability in phosphomolybdenum and metal chelation tests compared to the n-hexane extract.
3.3 The enzyme inhibitory potential of the essential oil and n-hexane extract of Olibanum
The enzyme inhibitory effects of the essential oil and n-hexane of Olibanum were investigated against several enzymes, including cholinesterase, α-glucosidase, α-amylase, and tyrosinase. The results are presented in Table 3. Except for α-amylase inhibition, in all other enzyme assays, the essential oil demonstrated a stronger effect compared to others. The n-hexane extract was only more active on α-amylase, compared to the essential oil.
3.4 In silico molecular docking study
The primary components of the essential oil, namely acetic acid octyl ester, nerolidol, and caprylic alcohol, along with the main compounds of the n-hexane extract, such as incensole, (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol, and 24-norursa-3,12-diene, were docked into the active sites of the five enzymes: NADPH oxidase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase. Those six compounds were selected as they represent the highest percentage in the major extract. As indicated in Table 4, all compounds revealed good binding scores on docking with these five targets.
For the NADPH oxidase, the six compounds achieved docking scores from −7.1 to −9.4 Kcal/mol, where acetic acid octyl ester and 24-norursa-3,12-diene were the best compounds, achieving scores of −8.4 and −9.4 Kcal/mol, respectively. Inspecting Fig 4., Acetic acid octyl interacted with Tyr159 and Tyr188 through hydrogen bond interactions and with Lys187 and Tyr188, through hydrophobic interactions, while 24-norursa-3,12-diene formed only hydrophobic interactions with Tyr159, Ile160, Lys187, Tyr188, Phe245, Ille297, Pro298, and Leu299.
For the BChE enzyme, the six compounds achieved docking scores from −8.1 to −10.6 Kcal/mol, where nerolidol and incensole were the best compounds, achieving scores of −10.6 and −10.5 Kcal/mol, respectively. As seen in Fig 5, nerolidol formed several hydrophobic interactions with Trp82, Leu125, Tyr128, Ala328, Tyr332, Trp430, His438, and one hydrogen bond with Tyr332. Similarly, incensole formed hydrophobic interactions with Trp82, Leu125, Tyr332, His438, and hydrogen bond interactions with Tyr128, Glu197, and His438.
The six compounds achieved docking scores ranging from −5.5 to −11.9 Kcal/mol against the tyrosinase enzyme. Acetic acid octyl ester and (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol achieved the best scores −11.9 and −8.7 Kcal/mol, respectively. As Fig 6 revealed, acetic acid octyl ester formed several interactions with His215, His377, His381, and Val391. Likewise, (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol interacted Asp212, His215, Glu216, Phe362, His381 and Val391.
In the docking with α-amylase, the major compounds achieved good scores ranging from −5.4 to −7.1 Kcal/mol. Amongst nerolidol and 24-norursa-3,12-diene were the best compounds with scorers −6.7 and −7.1 Kcal/mol, respectively. As seen in Fig 7, nerolidol interacted with Lys466, Tyr468, Lys474, and His476 through both hydrophobic and hydrogen bond interactions. On the other hand, 24-norursa-3,12-diene formed only hydrophobic interactions with Tyr468 and His476.
For α-glucosidase, the six studied compounds achieved excellent docking scores from −7.9 to −12.3 Kcal/mol. Nerolidol and (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol achieved docking scores of −12.3 and −10.2 Kcal/mol, respectively, ranking the best two compounds. Inspecting their interactions as shown in Fig 8, it was found that nerolidol interacted with Asp62, Tyr65, His105, Ile146, Phe166, Ala229, His332, Tyr389, and Arg400 through different hydrophobic and hydrogen bond interactions. Similarly, (1S,2E,4S,5R,7E,11E)-cembra-2,7,11-trien-4,5-diol interacted with Ile146, Phe147, Phe166, Phe206, Glu271, Asp333, Tyr389 and Arg400.
4. Discussion
Here, the essential oil and n-hexane extract of B. serrata were analyzed via GC/MS to identify and quantify their volatile components. As discussed in the results section, about 62 and 71 compounds were identified in the essential oil and n-hexane extract.
Boswellia serrata, also known as frankincense or olibanum, is widely used for the treatment of various medical conditions, viz., arthritis, rhinitis, asthma, and several cancers. Upon reviewing the literature on B. serrata, one study reported the in vitro anti-osteoarthritis activity of olebanum gum resin ethanol extract with its main components (keto-β-boswellic acid and 3-O-acetyl-11-keto-β-boswellic acid) [47]. Another study discussed the potential anti-inflammatory activity of Boswellia serrata in vitro using ELISA. The oleogum resin was extracted with n-hexane, where it was found to be rich with polysaccharides, mucilage, and proteins in a percentage of 35.91%, 34%, and 14.29%, respectively, and the extract showed 82% inhibition of IL-6 [48].
Another species of Boswellia, known as B. sacra (B. carterii) was evaluated as an antiepileptic agent through zebrafish and mouse epilepsy models. Different extracts were prepared, but the n-hexane extract presented the most potent antiepileptic activity. The n-hexane extract showed the presence of different triterpenes, including prenyl-bi-cyclo-germacrene derivative, β-boswellic acid, bosgermacrene A, 11-keto-β-boswellic acid, 3-O-acetyl-11-keto-β-boswellic acid, α-boswellic acid, 3-O-acetyl α-boswellic acid, and 3-O-acetyl β-boswellic acid [49].
B. serrata n-hexane was assessed as anti-inflammatory in the osteoarthritis model (collagen-induced arthritis) in rats. Biochemical markers such as lipid peroxidase, glutathione, catalase, superoxide dismutase and nitric oxide were tested together with inflammatory markers such as IL-1β, IL-6, TNF-α, IL-10, and IF-γ using ELISA [50,51].
Incensole is identified as the main potential component in Boswellia species, known for its strong anti-inflammatory properties. The content of incensole in three Boswellia species, namely B. papyrifera, B. sacra, and B. serrata was analyzed using HPLC. B. papyrifera resin methanol extract had the highest concentration of incensole (18.4%), followed by n-hexane (13.5%) and ethyl acetate (3.6%). At the same time, only trace amounts were found in the B. sacra fraction, and incensole was not detected in the fractions of B. serrata [52]. It is worth noting here that icensole was detected herein in our study in the n-hexane extract evaluated through GC/MS analysis, with a percentage of 28.56% and the oxidized derivative named icensole oxide (1.37%).
B. serrata oleogum resin was tested in vitro for potential anticancer activity against HepG2 and HCT 116 cancer cell lines. GC/MS analysis was performed for the petroleum ether extract of the oleogum resin. The main identified volatile constituents were tricosane (75.32%), sabinene (19.11%), terpinen-4-ol (14.64%), and terpinyl acetate (13.01%) together with cholesterol, stigmasterol, and ß-sitosterol as minor components. The petroleum ether extract showed a potent anticancer effect (IC50 = 5.82 μg/mL at 48 h) compared to doxorubicin (IC50 = 4.68 μg/mL at 48 h) for the HepG2 cell line. Regarding the HCT 116 cell line, the IC50 value was 6.59 μg/mL at 48 h compared to 5-fluorouracil (IC50 = 3.43 μg/mL at 48 h) [11].
Moreover, the n-hexane extract of the oleogum resin from B. serrata was assessed for its hepatoprotective effects against liver injuries induced by CCl4, paracetamol, and thioacetamide. Silymarin was used as the reference standard. The n-hexane extract notably decreased the elevated serum marker enzyme level and prevented the increase in liver weight in all three liver injury models [53]. The antioxidant potential of the hydrodistilled oils and n-hexane extracts were investigated using various methods. A single antioxidant test is insufficient to capture the complex, multifaceted mechanisms by which natural extracts exert antioxidant activity. Therefore, we selected a panel of assays that target different modes of action to ensure a more comprehensive evaluation. In particular, we utilized radical scavenging assays like DPPH and ABTS, as they assess the capacity of compounds to donate hydrogen atoms or electrons, neutralizing free radicals, and demonstrating direct radical-quenching abilities. We included reducing power assays such as CUPRAC and FRAP to assess the electron-donating capabilities of the extracts, a crucial aspect of antioxidant defense. Additionally, we employed the metal-chelating assay to assess the ability to bind transition metals like Fe² ⁺ , thereby preventing Fenton-type reactions that produce highly reactive hydroxyl radicals. The phosphomolybdenum assay was used to determine total antioxidant capacity, offering a comprehensive index of both water- and lipid-soluble antioxidant compounds.
In general, essential oils showed greater abilities among the methods. The n-hexane extract was only more active than the essential oil in the FRAP test. The observed antioxidant effect of essential oils can be explained by the presence of some volatile compounds. For example, the essential oil contained nerolidol and was described in previous work as an important antioxidant [54,55]. In addition to nerolidol, acetic acid octyl ester, α-pinene, and incensole may contribute to the observed antioxidant properties. However, because the n-hexane extract was richer in hydrocarbons than the essential oil, it showed lower antioxidant potential. In the literature, the essential oil of B. serrata gum has remarkable antioxidant properties. For example, a study by Gupta et al (2017) [56] examined the chemical composition of B. serrata essential oils for antioxidant properties, and they exhibited greater radical scavenging ability in the DPPH assay at a 100 µg/ml concentration. In another study by Irahal et al (2021), the essential oil B. serrata exhibited stronger protection against lipid peroxidation in the β-carotene/linoleic acid test system [57]. The essential oil of B. serrata also exhibited stronger radical scavenger ability than BHT in the DPPH assay, as reported by [58]. Similar results were also reported by [59].
Enzymes act as catalysts, speeding up many biochemical reactions. Their function is influenced by their unique structural shapes within biological systems. Enzyme inhibition occurs when an inhibitor molecule reduces or stops enzyme activity. This happens when the inhibitor interferes with the enzyme’s ability to bind to its natural substrate, thereby limiting the production of products.
In this study, we evaluated the inhibitory effects of the essential oil and n-hexane extract of B. serrata against several key enzymes. We selected the enzymes because they are associated with global health problems. For example, inhibiting AChE can increase the level of acetylcholine in the synaptic cleft, which can improve the cognitive function of Alzheimer’s patients. This phenomenon is also known as the cholinergic hypothesis and forms the basis of the main strategy for developing Alzheimer’s drugs [60]. In addition, amylase and glucosidase are the main enzymes involved in the hydrolysis of carbohydrates, and their inhibition can help to manage the blood glucose levels of diabetic patients [61]. Tyrosinase is the main enzyme involved in melanin synthesis, and thus its inhibition can address hyperpigmentation issues [62]. These disorders affect people all over the world, which is why we aim to provide a novel approach to managing them via the theory of enzyme inhibition.
Consistent with the antioxidant results, except for amylase inhibition, the essential oil showed stronger inhibitory effects than the n-hexane extract. Some constituents in essential oil can contribute to these abilities. For example, nerolidol has been reported as a significant AChE inhibitor in a previous study [63]. In addition, several studies have reported that nerolidol has a good neuroprotective effect. Furthermore, incensole prevented the formation of β-amyloid plaque in Alzheimer’s disease and thus can be considered a neuromodulator agent [64]. Alpha-pinene is a good anti-cholinesterase inhibitor in several studies [65]. In a previous study by Wu et al. (2020), cembran-type diterpenoids were reported as novel glucosidase inhibitors. Overall, B. serrata essential oil in particular may be a useful active ingredient in the production of novel drugs to address global health issues like diabetes and Alzheimer’s disease [66].
Understanding the molecular mechanism of compounds provides a futuristic guide for further drug development and optimization. Accordingly, five targets commonly found in many chronic diseases were selected as potential targets for docking of the compounds in the major extract. The docking results revealed the excellent ability of many compounds in the major extract to strongly bind and inhibit the selected targets. To this end, the docking results highlight the Hexane Extract and the Hydrodistilled Oil of Boswellia serrata as potential source for finding a cure for many diseases.
5. Conclusions
GC–MS analysis of the essential oil and n-hexane extract of Boswellia (olibanum oleogum) revealed a diverse profile of volatile terpenoids and related compounds. The essential oil exhibited significantly higher antioxidant and enzyme inhibitory activities than the n-hexane extract, indicating that its bioactive constituents play a major role in modulating oxidative and enzymatic pathways. These findings support the potential therapeutic value of olibanum essential oil in managing oxidative stress-related and age-associated disorders, including Alzheimer’s disease, Diabetes mellitus, and skin hyperpigmentation. This study provides scientific evidence for the traditional use of frankincense and highlights its potential as a source of natural compounds for drug and cosmetic development. Future investigations should aim to isolate and characterize the key active constituents, elucidate their molecular mechanisms, and assess their safety, pharmacokinetics, and efficacy through in vivo and clinical studies. Such work will be essential to fully establish the therapeutic relevance and translational potential of olibanum essential oil.
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