Structural characterisation of bioactive compounds of Gymnosporia senegalensis (Lam.) Loes. using advanced analytical technique like FT-IR, GC-MS and 1H-NMR spectroscopy

The present investigation was carried out to characterise bioactive components from G. senegalensis by using Fourier-transform infra-red (FT-IR) spectroscopy, 1H-nuclear magnetic resonance spectroscopy, and gas chromatography-mass spectrometry (GC-MS). The FTIR analysis confirmed the presence of > CH2, -CH3, C = C-C, C-H, C-F, C = C, -C = N-, C-C = N-, and -OH functional groups. The 1H-NMR spectrum revealed the presence of structures of four bioactive compounds i.e. tetratetracontana derivative, β-carotene, amyrin, and terpineol. GC-MS revealed the presence of different types of high and low molecular weight chemical entities with varying quantities including volatile and essential oil, monoterpenoid, tetraterpenoid, carotenoid, terpenoid, triterpenes, and nortriterpenes. From the results, it could be concluded that G. senegalensis contains various bioactive compounds of biological and pharmacological importance. Overall, this study will provide insight into the characterisation and development of drugs from medicinal plants.

Evaluating the Potential of Boswellia rivae to Provide Sustainable Livelihood Benefits in Eastern Ethiopia

Frankincense is an oleo-gum-resin collected from wild Boswellia spp. trees, and widely used in perfumery, cosmetics, aromatherapy, incense, and other industries. Boswellia rivae, growing in Ethiopia, Somalia, and Kenya, is one source of frankincense, but is little-commercialized compared to species such as B. sacra, B. frereana, and B. papyrifera. In this study, we examine the resin essential oil chemistry and harvesting systems of B. rivae in order to evaluate its potential for increased trade and potential positive livelihood benefits. Boswellia rivae produces an essential oil rich in α-thujene (0.1-12.4%), α-pinene (5.5-56.4%), β-pinene (0.3-13.0%), δ-3-carene (0.1-31.5%), p-cymene (1.4-31.2%), limonene (1.8-37.3%), β-phellandrene (tr-5.6%), trans-pinocarveol (0.1-5.0%), trans-verbenol (0.1-11.2%), and trans-β-elemene (0-5.7%), similar to major commercial species, although it is difficult to detect mixing of B. rivae and Commiphora africana resins from chemistry alone. The B. rivae trees are not actively tapped, so resin collection has a neutral impact on the health of the trees, and resin production is unaffected by drought. Consequently, collecting resins acts as a key income supplementing livestock herding, as well as a safety net protecting pastoral communities from the severe negative effects of climate change-exacerbated drought on livestock. Therefore, Boswellia rivae is well positioned chemically, ecologically, and socially to support expanded trade.

Conservation Assessment and Chemistry of Boswellia ogadensis, a Critically Endangered Frankincense Tree

Boswellia ogadensis is a critically endangered species of frankincense tree, restricted to a small area of the Shabelle river valley in southern Ethiopia. It has only been recorded from two botanical collecting trips, in 1972 and 2006, with no indication of the abundance, threats, or population status of the trees, and it was listed on the IUCN Red List of Endangered Species as "Critically Endangered" in 2018. More recent expeditions, in 2019 and 2021, were not able to locate the species, raising concerns about its continued survival. We carried out a field survey in June 2022 to re-locate the species, assess the threat level it is facing, and collect samples of resin for analysis. This survey revealed that B. ogadensis is present in more locations than previously recorded, and is more abundant than thought. While it is facing multiple threats, including grazing, cutting for firewood, and insect attacks, these threats vary geographically, and there are populations that appear to be healthy and regenerating well. While more research is needed, the current survey indicates that downlisting to "Endangered" status may be appropriate. Samples of resin were also collected and analyzed using gas chromatographic techniques, revealing that while the essential oil profile is similar to that of other Boswellia species (dominated by α-thujene, α-pinene, p-cymene, and terpenin-4-ol), there are chemical markers that can distinguish it from other sympatric Boswellia species, indicating the potential for this to be used as a tool to monitor whether B. ogadensis is being harvested alongside other more common Boswellia species.

Bridging the Chemical Profile and Biomedical Effects of Scutellaria edelbergii Essential Oils

The present study explored chemical constituents of Scutellaria edelbergii essential oils (SEEO) for the first time, extracted through hydro-distillation, and screened them against the microbes and free radicals scavenging effect, pain-relieving, and anti-inflammatory potential employing standard techniques. The SEEO ingredients were noticed via Gas Chromatography-Mass-Spectrometry (GC-MS) analysis and presented fifty-two bioactive compounds contributed (89.52%) with dominant volatile constituent; 3-oxomanoyl oxide (10.09%), 24-norursa-3,12-diene (8.05%), and methyl 7-abieten-18-oate (7.02%). The MTT assay via 96 well-plate and agar-well diffusion techniques against various microbes was determined for minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), IC₅₀, and zone of inhibitions (ZOIs). The SEEO indicated considerable antimicrobial significance against tested bacterial strains viz. Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterococcus faecalis and the fungal strains Fusarium oxysporum and Candida albicans. The free radicals scavenging potential was noticed to be significant in 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) as compared to 2,2′-azino-bis-3-ethylbenzotiazolin-6-sulfonic acid (ABTS) assays with IC₅₀ = 125.0 ± 0.19 µg/mL and IC₅₀ = 153.0 ± 0.31 µg/mL correspondingly; similarly, the antioxidant standard in the DPPH assay was found efficient as compared to ABTS assay. The SEEO also offered an appreciable analgesic significance and presented 54.71% in comparison with standard aspirin, 64.49% reduction in writhes, and an anti-inflammatory potential of 64.13%, as compared to the standard diclofenac sodium inhibition of 71.72%. The SEEO contain bioactive volatile ingredients with antimicrobial, free radical scavenging, pain, and inflammation relieving potentials. Computational analysis validated the anti-inflammatory potential of selected hit “methyl 7-abieten-18-oate” as a COX-2 enzyme inhibitor. Docking results were very good in terms of docked score (−7.8704 kcal/mol) and binding interactions with the functional residues; furthermore, MD simulation for 100 ns has presented a correlation with docking results with minor fluctuations. In silico, ADMET characteristics supported that methyl 7-abieten-18-oate could be recommended for further investigations in clinical tests and could prove its medicinal status as an anti-inflammatory drug.

Comparison of Volatile Constituents Present in Commercial and Lab-Distilled Frankincense (Boswellia carteri) Essential Oils for Authentication

A comparative analysis of the chemical constituents present in twenty-one commercial and two lab-distilled frankincense (Boswellia carteri) essential oils was carried out using gas chromatography-mass spectrometry (GC-MS) and chiral gas chromatography-mass spectrometry (CGC-MS) for authentication. Out of the twenty-one commercial samples, six were adulterated with synthetic limonene, three were contaminated with synthetic octyl acetate, three were adulterated with castor oil, and two samples each were contaminated with frankincense resin and Boswellia occulta species, respectively, and one was contaminated with the Boswellia serrata species. Additionally, one sample was contaminated with phthalates as well as a cheap essential oil with similar compositions. Furthermore, one sample was adulterated with copaiba resin and frankincense resin in combination with synthetic octyl acetate. Additionally, one was contaminated with Boswellia serrata species, which was further adulterated with castor oil and frankincense resin. To the best of our knowledge, this is the first report to compare the enantiomeric distribution of chiral terpenoids present in commercial frankincense essential oil with lab-distilled frankincense oil for authentication. The CGC-MS analysis showed the presence of a total of eight chiral terpenoids in lab-distilled frankincense essential oils, which can be used as chemical fingerprints for the authentication of frankincense essential oil.

Characterization of Boswellia rivae Engl Resin as a Potential Use for Pharmaceutical Excipient

Pharmaceutical excipients derived from natural sources like resins are nowadays meritoriously used in the formulation of drugs. Resins of natural origin have many advantages over chemically synthesized substances; they are safer, nontoxic, less expensive, biodegradable, and widely available. To our knowledge, resins from plants have been not sufficiently explored for application in pharmaceutical formulations. Thus, in the present study, a resin isolated from Boswellia rivae Engl was characterized for its potential use as a pharmaceutical excipient. Method. The resin was extracted from the oleo gum resin of Boswellia rivae Engl, which involved the removal of volatile oils, gum, and Boswellic acid contents. The dried resin powder was then characterized for its micromeritic properties, heavy metal contents, moisture content, moisture absorption power, pH, solubility, swelling property, and acute toxicity profile. Moreover, the crystal nature and the chemical functionality of the resin were evaluated by using X-ray diffraction and Fourier transform infrared spectrometry, respectively. Results. The yield of the neutral resin was 13.17%, and the powder was pale yellow and had irregular surfaces. The resin was freely soluble in organic solvents but almost insoluble in water. The moisture content of the dried extract was 2.5% while its moisture absorption capacity was 2.5%, 4%, and 5.47% at 40%, 60%, and 75% RH, respectively. Besides, the maximum swelling capacities of the resin observed were 40%, 37%, and 30% at 350C, 300C, and 250C, respectively. The bulk powder exhibited a 1.21 Hausner ratio, 36.497 angles of repose, and 17.03% Carr's index, indicating the fair flowability of the powder. Heavy metals such as zinc, chromium, and cobalt were detected at a low level while elements like copper, manganese, lead, and cadmium were absent. The X-ray diffraction study revealed that the crystallinity index of the powder was 42.7% with a crystal size of 994.5A. The Boswellia resin could be safe in mice up to 3 g/kg of their body weight. In conclusion, the physicochemical properties of the resin powder investigated reveal its potential application as pharmaceutical additives in the formulation of modified release solid dosages forms like tablets and microcapsules.

Inter-Tree Variation in the Chemical Composition of Boswellia papyrifera Oleo-Gum-Resin

Frankincense is a fragrant resin produced by Boswellia species, and has been used for centuries as a perfume, medicine, and incense, and is an important cosmetic and therapeutic product today. A number of studies have been conducted on the resin essential oils, but many have used commercial sources outside of the country of origin, leading to potential taxonomic confusion or misidentification. Individual Boswellia papyrifera resin samples were each obtained directly from 11 individual trees in Sudan, hydrodistilled, the volatile phytochemicals determined by gas chromatographic methods, and the chemical compositions subjected to cluster analysis. All samples were very similar, with high levels of octyl acetate (49.5%-81.0%) and octanol (6.5%-13.7%), and varying levels of diterpenoids (6.6%-32.7%). The cluster analysis indicated 3 highly similar groups, defined by (1) relatively higher levels of octyl acetate (58.9%-81.0%), but with low levels of diterpenoids (6.6%-18.6%); (2) relatively lower levels of octyl acetate (49.5%-61.3%), but with a higher proportion of diterpenoids (19.0%-22.8%); and (3) with octyl acetate (51.6%) and diterpenoids (32.7%).

New Alk(en)ylhydroxycyclohexanes with Tyrosinase Inhibition Potential from Harpephyllum caffrum Bernh. Gum Exudate

This work presents the first report on the phytochemical investigation of Harpephyllum caffrum Bernh. gum exudate. A known cardanol, 3-heptadec-12'-Z-enyl phenol (1) and three new alk(en)ylhydroxycyclohexanes, namely, (1R,3R)-1,3-dihydroxy-3-[heptadec-12'(Z)-enyl]cyclohexane (2) (1S,2S,3S,4S,5R)-1,2,3,4,5-pentahydroxy-5-[octadec-13'(Z)-enyl]cyclohexane (3) and (1R,2S,4R)-1,2,4-trihydroxy-4-[heptadec-12'(Z)-enyl]cyclohexane (4) were isolated from the gum. The structures of the compounds were determined by extensive 1D and 2D NMR spectroscopy and HR-ESI-MS data. The ethanolic extract of the gum was found to be the most potent tyrosinase inhibitor with IC₅₀ of 11.32 µg/mL while compounds 2 and 3, with IC₅₀ values of 24.90 and 26.99 µg/mL, respectively, were found to be potential anti-tyrosinase candidates from the gum. Gum exudate may be a potential source for non-destructive harvesting of selective pharmacologically active compounds from plants. The results also provide evidence that H. caffrum gum may find application in cosmetics as a potential anti-tyrosinase agent.

The Chemical Composition of Single-Tree Boswellia frereana Resin Samples

Frankincense is an aromatic terpenoid oleo-gum resin produced by trees in the genus Boswellia. It has been used for medicinal and religious purposes for millennia, and is today an important component in perfume and aromatherapy. The resin of Boswellia frereana is especially prized, and has been found to contain a high proportion of monoterpenes. However, previous studies have relied on commercial samples; in this study, we characterize the compositions of essential oil and DCM extract samples from 12 individual B frereana trees. The triterpenoid fraction was largely consistent between samples, with lupeol (14.7%-32.5%), α-amyrin (13.0%-25.2%), 3- epi-lupeol (6.4%-14.2%), and β-amyrin (5.3%-8.0%) as the primary constituents. The essential oil showed more intersample diversity, but still represented a single, variable chemotype characterized by a moderate to high level of α-thujene (14.5%-43.9%) and a varying, often significant, level of α-pinene (3.0%-63.0%).

Compositional analysis of the essential oil of Boswellia dalzielii frankincense from West Africa reveals two major chemotypes

Frankincense, an oleoresin produced by Boswellia species, has historical medicinal and religious significance, and is today used extensively for its essential oil. Boswellia dalzielii, a species found in West Africa, is one of the few frankincense species for which there is no information on the oleoresin essential oil. In order to correct this deficiency, the chemical compositions of the essential oil hydrodistilled from 21 samples of oleoresin taken directly from B. dalzielii trees in northern Nigeria, were analyzed by gas chromatography - mass spectrometry as well as chiral gas chromatography. In addition, a hierarchical cluster analysis was performed on the essential oil compositions from the 21 oleoresin samples from northern Nigeria as well as two samples from Ghana. The essential oil fractions obtained by hydrodistillation of B. dalzielii oleoresins were dominated by α-pinene (21.7-76.6%), followed by α-thujene (2.0-17.6%), myrcene (up to 35.2%), p-cymene (0.3-15.6%), and limonene (1.1-32.9%). The levorotatory enantiomers predominated for the monoterpenes with 98.1 ± 1.5% (-)-α-thujene, 99.2 ± 0.5% (-)-α-pinene, and 96.8 ± 1.4% (-)-β-pinene. Limonene showed the largest variation in enantiomeric distribution [67.3 ± 12.1% (-)-limonene]. The cluster analysis revealed two major chemotypes, one dominated by α-pinene and one much rarer chemotype rich in myrcene.

Chemical Composition of the Oleogum Resin Essential Oils of Boswellia dalzielii from Burkina Faso

Frankincense, the oleogum resin from members of Boswellia, has been used as medicine and incense for thousands of years, and essential oils derived from frankincense are important articles of commerce today. A new source of frankincense resin, Boswellia dalzielii from West Africa has been presented as a new, alternative source of frankincense. In this work, the oleogum resins from 20 different Boswellia dalzielii trees growing in Burkina Faso, West Africa were collected. Hydrodistillation of the resins gave essential oils that were analyzed by GC-MS and GC-FID. The essential oils were dominated by α-pinene (21.0%–56.0%), followed by carvone (2.1%–5.4%) and α-copaene (1.8%–5.0%). Interestingly, there was one individual tree that, although rich in α-pinene (21.0%), also had a substantial concentration of myrcene (19.2%) and α-thujene (9.8%). In conclusion, the oleogum resin essential oil compositions of B. dalzielii, rich in α-pinene, are comparable in composition to other frankincense essential oils, including B. sacra, B. carteri, and B. frereana. Additionally, the differences in composition between samples from Burkina Faso and those from Nigeria are very slight. There is, however, a rare chemotype of B. dalzielii that is dominated by myrcene, found both in Burkina Faso as well as Nigeria.

Organic Certification is Not Enough: The Case of the Methoxydecane Frankincense

Frankincense, the oleo-gum-resin of Boswellia trees, has been an important religious and medicinal element for thousands of years, and today is used extensively for essential oils. One of the most popular frankincense species is Boswellia sacra Flueck. (syn. Boswellia carteri Birdw.) from Somalia and Somaliland. Recent increases in demand have led to many areas being overharvested, emphasizing the need for incentives and monitoring for sustainable harvesting, such as certification schemes. Concurrently, a new chemical component, called methoxydecane, has emerged in oils claimed to be B. carteri, suggesting the possibility of a chemical marker of overharvesting or other stress that could aid in monitoring. To find the source of this new chemical component, we sampled resin directly from trees in areas producing the new methoxydecane chemotype. This revealed that methoxydecane comes not from Boswellia carteri, but from a newly described frankincense species, Boswellia occulta. The presence of Boswellia occulta oil in essential oil sold as pure B. carteri, including certified organic oil, emphasizes the current lack of traceability in the supply chain and the ineffectiveness of organic certification to secure purity and sustainable harvesting in wildcrafted species.

Ex-vivo intestinal absorption study of boswellic acid, cyclodextrin complexes and poloxamer solid dispersions using everted gut sac technique

Acetyl- Keto-β-boswellic acid (AKBA) is a pentacyclic triterpenic acid found in gum resin of Boswellia serrata. Even though it is shown to have anti-inflammatory activity, its bioavailability gets limited due to its poor aqueous solubility and permeability. The present study, hence, deals in enhancement of the intestinal absorption of AKBA from total boswellic acid fraction (TA fraction) using cyclodextrin (CD) and poloxamer solid dispersion (PXM SDs) formulations. Absorption studies were performed using the everted gut sac model prepared from rat jejunum. The glucose uptake assay was performed to show viability of gut sac tissue. The apparent permeability (P_app) value of AKBA from TA fraction was 1.08 ± 0.17 × 10^-6 which was found to be increased by 10-14 fold with CD complex and SD formulations. The intestinal absorption studies showed highest absorption of AKBA from HP-β-CD complex and PXM 407 SD as compared to that from TA fraction. From this study, it can be concluded that HP-β-CD and PXM 407 effectively enhanced intestinal absorption through improved solubility, highlighting their role as efficient drug delivery agents and bioavailability enhancers.

Chemical Variation in Essential Oils from the Oleo-gum Resin of Boswellia carteri: A Preliminary Investigation

Frankincense, the oleo-gum resin of Boswellia species, has been an important element of traditional medicine for thousands of years. Frankincense is still used for oral hygiene, to treat wounds, and for its calming effects. Different Boswellia species show different chemical profiles, and B. carteri, in particular, has shown wide variation in essential oil composition. In order to provide insight into the chemical variability in authentic B. carteri oleoresin samples, a hierarchical cluster analysis of 42 chemical compositions of B. carteri oleo-gum resin essential oils has revealed at least three different chemotypes, i) an α-pinene-rich chemotype, ii) an α-thujene-rich chemotype, and iii) a methoxydecane-rich chemotype.

Genomic sequencing and microsatellite marker development for Boswellia papyrifera, an economically important but threatened tree native to dry tropical forests

Microsatellite (or simple sequence repeat, SSR) markers are highly informative DNA markers often used in conservation genetic research. Next-generation sequencing enables efficient development of large numbers of SSR markers at lower costs. Boswellia papyrifera is an economically important tree species used for frankincense production, an aromatic resinous gum exudate from bark. It grows in dry tropical forests in Africa and is threatened by a lack of rejuvenation. To help guide conservation efforts for this endangered species, we conducted an analysis of its genomic DNA sequences using Illumina paired-end sequencing. The genome size was estimated at 705 Mb per haploid genome. The reads contained one microsatellite repeat per 5.7 kb. Based on a subset of these repeats, we developed 46 polymorphic SSR markers that amplified 2-12 alleles in 10 genotypes. This set included 30 trinucleotide repeat markers, four tetranucleotide repeat markers, six pentanucleotide markers and six hexanucleotide repeat markers. Several markers were cross-transferable to Boswellia pirrotae and B. popoviana. In addition, retrotransposons were identified, the reads were assembled and several contigs were identified with similarity to genes of the terpene and terpenoid backbone synthesis pathways, which form the major constituents of the bark resin.