Anti-mycobacterial activity of polyketides from Penicillium sp. endophyte isolated from Garcinia nobilis against Mycobacterium smegmatis

Objective/background: According to estimates by the World Health Organization, there were 9.6 million new tuberculosis (TB) cases in 2014: 5.4 million among men, 3.2 million among women, and 1.0 million among children. There were also 1.5 million TB deaths. Although there are potent anti-TB molecules, the misuse of these drugs in addition to inconsistent or partial treatment have led to the development of multidrug-resistant TB and extensively drug-resistant TB. It is established that plants harbor microorganisms, collectively known as endophytes, which also produce metabolites. Exploring the as-yet untapped natural products from the endophytes increases the chances of finding novel and active compounds. The present study was aimed to investigate the antimycobacterial activity of the crude extract and compounds isolated from Penicillium sp. endophyte associated with Garcinia nobilis against Mycobacterium smegmatis. Methods: Liquid culture obtained from the fermentation of Penicillium sp. was extracted using ethylacetate and the liquid chromatography–mass spectrometry monitored fractionation of crude extracts yielded six compounds. Their structures were elucidated with spectroscopic analyses including two-dimensional nuclear magnetic resonance, high resolution mass spectrometry by dereplication using Antibase, and by comparison to literature data. All compounds and the crude extract from the liquid medium were evaluated for their antimycobacterial activity against M. smegmatis. Results: In this study, the activity of penialidins A–C (1–3), citromycetin (4), p-hydroxy phenyl glyoxalaldoxime (5), and Brefeldin A (6) were tested against nonpathogenic M. smegmatis. Penialidin C was the most active compound with a minimum inhibitory concentration of 15.6μg/mL. Conclusion: Isolated compounds from Penicillium sp. harbored in G. nobilis exhibited promising antimycobacterial activity against M. smegmatis thus supporting the immensity of the potential of antimycobacterial drug discovery from endophytes from medicinal plants. Penialidin C could further be investigated for antimycobacterial drug development

Pentacyclic triterpenoids and other constituents isolated from the leaves of Gambeya lacourtiana and their antibacterial activity

Talla RM, Jouda J-B, Mbazoa CD, et al. Pentacyclic triterpenoids and other constituents isolated from the leaves of Gambeya lacourtiana and their antibacterial activity. Biochemical Systematics and Ecology. 2021;98: 104322.The phytochemical study was done on the leaves of Gambeya lacourtiana. This plant has been used in traditional medicine to treat of different ailments such as uterine heamorrhage, metritis and other vaginal infections. Chromatographic fractionation and purification on the leaves crude extract afforded lupeol acetate (1), lupenone (2), lupeol (3), taraxerol (4) stigmasterol (5), erythrodiol (6), chamaedrydiol (7), methyl pheophorbide-a (8), corosolic acid (9), tormentic acid (10), epicatechin (11) and 22-dihydrospinasterol 3-O-β-D-glucopyranoside (12). The structures of compounds 1–12 were elucidated on the basis of 1D and 2D NMR, mass spectrometric and the spectroscopic data as well as comparison with the literature. Compounds 4, 7–10 and 12 were isolated for the first time from Gambeya genus. Crude extract, fractions and compounds 6–12 were evaluated for their antibacterial activity. Methyl pheophorbide-a (8) demonstrated moderate activity against Salmonella typhi CPC with MIC values of 62.5 μg/mL. The chemophenetic significance of these compounds is also discussed

Secondary metabolites from <i>Aspergillus japonicus</i> CAM231, an endophytic fungus associated with <i>Garcinia preussii</i>

<p>Chemical investigation of <i>Aspergillus japonicus</i> CAM231, isolated from the leaf of <i>Garcina preussii</i> collected in Cameroon, yielded two new compounds; one pyrone derivative, hydroxy neovasinin (<b>1</b>) and one phenol derivative, asperolan (<b>2</b>), together with two known compounds neovasifurarone B (<b>3</b>) and variecolin (<b>4</b>). The structures of the two new compounds were established using intensive NMR spectroscopy and HRMS spectra in comparison with data found in literature. The structure of compound <b>1</b> was confirmed by single-crystal X-ray crystallographic analysis in combination with NOESY experiment. The new compounds were screened for their cytotoxic and antibacterial properties; however, the tested compounds displayed no significant activities.</p

Oligoamide, a new lactam from the leaves of <i>Angylocalyx oligophyllus</i>

<p>A new lactam, oligoamide (<b>1</b>), along with three known compounds (<b>2</b>–<b>4</b>), stigmasterol-3-O-β-D-glucopyranoside (<b>2</b>), formononetin (<b>3</b>) and (-)-pinitol (<b>4</b>) were isolated from the CH₂Cl₂/CH₃OH (1:1) extract of the leaves of <i>Angylocalyx oligophyllus</i> by chromatographic separation. Their structures were elucidated on the basis of spectroscopic analysis (UV, IR, MS, 1D, and 2D NMR). Compound <b>1</b> was found to have weak antioxidant and urease inhibitory potential.</p