Methyl betulinate

The ethyl acetate fraction, the stem bark and the residual methanolic extracts from the leaves of Cola heterophylla (Sterculiaceae) led to the isolation of two new compounds: Heterophynone (1) and methyl ester of Colic acid (6), along with four known triterpenes: betulinic acid (2), oleanolic acid (3), ursolic acid (4) and chletric acid (5). Structures of compounds were established by different spectroscopic methods that included 1D and 2D NMR experiment. The antimicrobial activity of isolated compounds was evaluated against two yeasts, Candida Albicans NR 29456 and Candida Krusei 1415; and five Gram-positive bacterial, Salmonella enteric Serovar Muenchem, Salmonella enteric Serovar Thyphimurium, Staphylococcus aureus NR 46003, Staphylococcus aureus NR46374 and Pseudomonas aeruginosa HM 601). Among tested compounds, Heterophynone was found to be the most active with significant antimicrobial activity against Salmonella enteric Serovar Thyphimurium (MIC = 7.82 μg/mL and MBC = 62.5 μg/mL) and good activity against Candida Albicans NR 29456 (MIC = 62.5 μg/mL).

It is known that Senna obtusifolia has been used in medicine since ancient times due to the content of many valuable compounds with a pro-health effect. One of them is betulinic acid, which is a pentacyclic triterpene with antimalarial, antiviral, anti-inflammatory and anticancer properties. In this work, a continuation of our previous research, an attempt was made to increase the level of betulinic acid accumulation by the cultivation of transgenic hairy roots that overexpress the squalene synthase gene in a 10 L sprinkle bioreactor with methyl jasmonate elicitation. We present that the applied strategy allowed us to increase the content of betulinic acid in hairy root cultures to the level of 48 mg/g dry weight. The obtained plant extracts showed a stronger cytotoxic effect on the U87MG glioblastoma cell line than the roots grown without elicitors. Additionally, the induction of apoptosis, reduction of mitochondrial membrane potential, chromosomal DNA fragmentation and activation of caspase cascades are demonstrated. Moreover, the tested extract showed inhibition of topoisomerase I activity.

Extraction of the aerial part of Rinorea yaundensis has led to the isolation of a new monoterpene indole alkaloid (1) along with 10 known compounds (2-11) for the first time from this plant. Their structures were determined by HRMS and NMR spectroscopic analyses as yaundentine hydrochloride (1), Nb-oxide of iso-reserpiline (2), iso-reserpiline (3), iso-carapanaubine (4), lichenxanthone (5), stigmastane-3,6-dione (6), methyl β-orcinol carboxylate (7), β-sitosterol-3-O-β-D-glucoside (8), betulinic acid (9), ursolic acid (10) and benzoic acid (11) while the stereochemistry and absolute configuration of 1 was confirmed by single crystal x-ray crystallography and circular dichroism CD spectrum. Yaundentine hydrochloride (1) exhibited pronounced antioxidant, urease and lipoxygenase inhibitory activities with IC50 values of 35.6 ± 0.23, 20.3 ± 0.58 and 29.6 ± 0.77 µM, respectively. Compound 1 also showed good antimicrobial activity against some Gram positive and negative bacteria.