A novel pentacyclic triterpene acid from the stem barks of Combretum fragrans F. Hoffm (Combretaceae)

A phytochemical study was carried out on stem bark of Combretum fragrans F. Hoffm., a medicinal plant belonging to the Combretaceae family and used traditionally in the treatment of various ailments. Column chromatography separation on silica gel of the crude methanol extract from stem barks of C. fragrans led to the isolation of a new pentacyclic triterpene acid, with a 3,6-epoxide bridge and trivially named as fragransinic acid (1), along with four known compounds: betulin (2), betulinic acid (3), bellericagenin B (4) and a mixture of β-sitosterol (5) and stigmasterol (6). Structures were elucidated by extensive spectroscopic analyses including 1D and 2D NMR, mass spectrometry as well as by comparison with literature data. The above compounds were isolated for the first time from C. adenogonium. Implications for chemosystematics and traditional medicine were briefly discussed.

Chemical constituents from Cordia myxa L. (Boraginaceae) and their antibacterial activity

Chemical investigation of Cordia myxa L. (Boraginaceae) resulted in the isolation of the following ten known compounds: 1-naphthaleneacetic-5-carboxy-1,2,3,4,4a,7,8,8a-octahydro-1,2,4a-trimethyl-[1S-(1α,2β, 4a,8aα)]-acid (1), hexacosanoate-1-glyceryl (2), 3β-urs-12,20(30)-diene-27,28-dioic acid (3), 3β-D-glucopyranosylurs-12,20(30)-diene-27,28-dioic acid (4), stigmasterol (5), stigmasterol-3-O-β-D-glucopyranoside (6), oleanolic-acid (7), 3-O-acetyl-oleanolic acid (8), betulin (9) and spinasterol-3β-O-D-glucopyranoside (10). The isolated compounds were characterised by using spectroscopic methods, 1D and 2D NMR, mass spectroscopy (ESI-MS) and by comparison with the literature data. To the best of our knowledge, compounds 1, 3, 4, 8 and 10 were isolated for the first time from the Cordia genus. This result improves the chemotaxonomy knowledge of the Cordia genus. The antibacterial activities were performed by the Muller-Hinton agar diffusion method. The antibacterial activities were studied on Salmonella typhi, Staphylococcus aureus, Vibrio cholerae, Pseudomonas aeruginosa and Escherichia coli ATCC 25922. Compounds 8 and 9, at 20.0 mg/mL resulted to be effective antimicrobial against E. coli, V. cholerae and P. aeruginosa.

In vitro α-glucosidase inhibitory activity of isolated compounds and semisynthetic derivative from aerial parts of Erythrina senegalensis DC

The current study was conducted to isolate the phytoconstituents from Erythrina senegalensis leaves and stem bark and evaluate their inhibitory activity against α-glucosidase, digestive enzyme related to diabetes mellitus. Phytochemical investigation of the leaves resulted in the isolation of three saponins (3-5), two triterpenoids (7 and 8) and two steroids (10a and 10b) as inseparable mixture, while one saponin (6), one triterpenoid (9) and one mixture of two cinnamates (2a and 2b) were isolated from the stem bark. Except for compounds 2 b, 7, 8, 10a and 10 b all the isolated compounds are reported here for the first time from the genus Erythrina. Acetylation of the mixture of two cinnamates (2a and 2b) led to a new diester derivative (1) trivially called erythrinamate. The extracts and pure compounds (3, 4, 6) showed good α-glucosidase inhibitory activity compared to the standard drug acarbose. The findings suggest that saponins of E. senegalensis could be used to develop potential anti-hyperglycemic drugs.

Nutritional and pharmacological potentials of orphan legumes: Subfamily faboideae

Legumes are a major food crop in many developing nations. However, orphan or underutilized legumes are domesticated legumes that have valuable properties but are less significant than main legumes due to use and supply restrictions. Compared to other major legumes, they are better suited to harsh soil and climate conditions, and their great tolerance to abiotic environmental circumstances like drought can help to lessen the strains brought on by climate change. Despite this, their economic significance in international markets is relatively minimal. This article is aimed at carrying out a comprehensive review of the nutritional and pharmacological benefits of orphan legumes from eight genera in the sub-family Faboidea, namely Psophocarpus Neck. ex DC., Tylosema (Schweinf.) Torre Hillc., Vigna Savi., Vicia L., Baphia Afzel. ex G. Lodd., Mucuna Adans, Indigofera L. and Macrotyloma (Wight & Arn.) Verdc, and the phytoconstituents that have been isolated and characterized from these plants. A literature search was conducted using PubMed, Google Scholar, and Science Direct for articles that have previously reported the relevance of underutilized legumes. The International Union for Conservation of Nature (IUCN) red list of threatened species was also conducted for the status of the species. References were scrutinized and citation searches were performed on the study. The review showed that many underutilized legumes have a lot of untapped potential in terms of their nutritional and pharmacological activities. The phytoconstituents from plants in the subfamily Faboideae could serve as lead compounds for drug discovery for the treatment of a variety of disorders, indicating the need to explore these plant species.

Antimicrobial and α-glucosidase inhibitory activities of chemical constituents from Gardenia aqualla (Rubiaceae)

An aliphatic alkene namely pentapentacontene (4) was isolated for the first time from a natural source, Gardenia aqualla, along with fourteen other compounds including nonacosanol (1), tetratriacontanol (2), octatriacontanol (3), β-sitosterol (5) and stigmasterol (6), daucosanol (7), ursolic acid (8), uvaol (9), 3β,19α,23β,24α-tetrahydroxyurs-12-en-28-oic acid (10), lupenone (11), oleanolic acid (12), vanillin (13), vanillic acid (14) and D-mannitol (15). α-glucosidase inhibitory assay revealed that MeOH and EtOAc extracts of leaves had the best activity with IC₅₀ of 9.65 and 20.03 µg/ml respectively. All the tested compounds showed dose dependent inhibition of α-glucosidase and some of them were found to be comparable to acarbose. Compound 10 was the most potent with IC₅₀ = 1.72 μM. It also showed the most interesting antibacterial activity, against the isolate strain of S. typhi and P. aeruginosa and also exhibited the most significant antifungal activities against all the tested yeasts.

An α-Sophoradiol Glycoside from the Root Wood of Erythrina senegalensis DC. (Fabaceae) with α-Amylase and α-Glucosidase Inhibitory Potential

Phytochemical study of the roots of Erythrina senegalensis led to the isolation of a new α-sophoradiol glycoside, erythrinoside (1), together with four known compounds, lupeol (2), α-sophoradiol (3), isoneorautenol (4) and D-mannitol (5). The structures of the compounds were elucidated using spectroscopic data including 1D and 2D NMR, mass spectrometry and by comparison made with some data reported previously; the samples (extracts and compounds) were also subjected to antidiabetic assay. Erythrinoside and isoneorautenol exhibited good α-amylase inhibitory potential of 54.6% and 53.3%, respectively, compared to acarbose (72.5%) at 400 µg/mL. With α-glucosidase, all samples showed promising inhibition percentages above 50% at 200 µg/mL. In the α-glucosidase assay, the ethyl acetate extract (65.5%), methanol extract (72.1%), erythrinoside (63.3%) and isoneorautenol (66.0%) had percentage inhibitions closer to that of acarbose (69.0%) at 200 µg/mL. The methanol extract (IC50 = 81.2 ± 0.9 µg/mL) was more active than acarbose (IC50 = 94.5 ± 0.7 µg.mL) in the α-glucosidase assay. The inhibition of α-amylase and α-glucosidase indicates that E. senegalensis extracts and compounds could be used to manage diabetic conditions.

Sterols and Triterpenes from Dobera glabra Growing in Saudi Arabia and Their Cytotoxic Activity

A new lupane caffeoyl ester, lup-20(29)-ene 3β-caffeate-30-al (7), and a new oleanane-type triterpene, 3β-hydroxyolean-13(18)-en-12-one (17), were isolated from the aerial parts of Dobera glabra (Forssk), along with ten known triterpenes, including seven lupane-type lupeol (1), 30-nor-lup-3β-ol-20-one (2), ∆1-lupenone (3), lup-20(29)-en-3β,30-diol (4), lupeol caffeate (5), 30-hydroxy lup-20(29)-ene 3β-caffeate (6), and betunaldehyde (8); three oleanane-type compounds were also identified, comprising δ-amyrone (15), δ-amyrin (16), and 11-oxo-β-amyrin (18); together with six sterols, comprising β-sitosterol (9), stigmasterol (10), 7α-hydroxy-β-sitosterol (11), 7α-hydroxy-stigmasterol (12), 7-keto-β-sitosterol (13), and 7-keto-stigmasterol (14). Their structures were elucidated using a variety of spectroscopic techniques, including 1D (1H, 13C, and DEPT-135 13C) and 2D (1H-1H COSY, 1H-13C HSQC, and 1H-13C HMBC) nuclear magnetic resonance (NMR) and accurate mass spectroscopy. Subsequently, the different plant extracts and some of the isolated compounds (1-9, 11 and 13) were investigated for their possible cytotoxic activity in comparison to cisplatin against a wide array of aggressive cancer cell lines, such as colorectal cancer (HCT-116), hepatocellular carcinoma (HepG-2), and prostate cancer (PC-3) cell lines. Compound 11 displayed broad cytotoxicity against all of the tested cell lines (IC50 ≅ 8 µg/mL in all cases), and a high safety margin against normal Vero cells (IC50 = 70 µg/mL), suggesting that 11 may be a highly selective and effective anticancer agent candidate. Notably, the evidence indicated that the mode of action of compound 11 could possibly consist of the inhibition of phosphodiesterase I (80.2% enzyme inhibition observed at 2 µM compound concentration).

α-Glucosidase Inhibition and Molecular Docking Studies of Natural Brominated Metabolites from Marine Macro Brown Alga Dictyopteris hoytii

Bioassay guided isolation of the methanolic extract of marine macro brown alga Dictyopteris hoytii afforded one new metabolite (ethyl methyl 2-bromobenzene 1,4-dioate, 1), one new natural metabolite (diethyl-2-bromobenzene 1,4-dioate, 2) along with six known metabolites (3-8) reported for the first time from this source. The structure elucidation of all these compounds was achieved by extensive spectroscopic techniques including 1D (1H and 13C) and 2D (NOESY, COSY, HMBC and HSQC) NMR and mass spectrometry and comparison of the spectral data of known compounds with those reported in literature. The in vitro α-glucosidase inhibition studies confirmed compound 7 to be the most active against α-glucosidase enzyme with IC50 value of 30.5 ± 0.41 μM. Compounds 2 and 3 demonstrated good inhibition with IC50 values of 234.2 ± 4.18 and 289.4 ± 4.91 μM, respectively, while compounds 1, 5, and 6 showed moderate to low inhibition. Furthermore, the molecular docking studies of the active compounds were performed to examine their mode of inhibition in the binding site of the α-glucosidase enzyme.