Phytochemical constituents of Vangueria infausta: their radical scavenging and antimicrobial activities

Abstract

A new biflavonoid, 5,7,3',5'',7'',4'''-hexahydroxy (4'-O-3''')-biflavone (1) and a polyketide derivative, methylcylohex-1-ene (3) [previously reported only as a synthetic compound] were isolated from aerial parts of Vangueria infausta. In addition, eight other known flavonoids viz. (-)-epicatechin, epiafzelechin, dihydrokaempferol, quercetin, luteolin (2), dihydroquercetin-3'-Oglucoside, daidzein and genistein were also isolated from this plant. Structures were identified using 1D-and 2D NMR experiments as well as ESI-MS, IR and UV spectra. The new biflavonoid 1 showed higher radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent compared to ascorbic acid (standard) using a spectrophotometric method. Compound 1 was less sensitive to Gram-positive and Gram-negative bacterial strains and yeast (Candida mycoderma) compared to luteolin and quercetin on the Bioautographic Agar Overlay Assay.

The chemistry and bioactivity of Southern African flora II: flavonoids, quinones and minor compound classes

“…60,61 Mbukwa et al isolated the new biavonoid 5,7,3 0 ,5 00 ,7 00 ,4 000 -hexahydroxy(4 0 -O-3 000 )-biavone (31) together with the known compounds (À)-epicatechin (20), epiafzelechin (32), dihydrokaempferol (33), quercetin (34), luteolin (35), dihydroquercetin-3 0 -O-glucoside (36), daidzein (37) and genistein (38) from aerial parts of Vangueria infausta (Rubiaceae). 62 Compound 31 showed higher radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent compared to ascorbic acid (standard) using a spectrophotometric method. But compound 31 was less sensitive to Grampositive and Gram-negative bacterial strains and yeast (Candida mycoderma) compared to 34 and 35 on the Bioautographic Agar Overlay Assay.…”

“…90 Ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) was investigated as an ultrafast, accurate, and sensitive method in the quantication of the main compounds in 101 Aloe ferox exudates, harvested in South Africa. 91 The main compounds were shown to be the chromones; aloeresin A (59), aloesin (60) and the anthrones aloin A (61) and aloin B (62). Even though the identied compounds have not been tested, this plant is known to possess laxative and cathartic effects.…”

Ethnomedicinal Uses, Phytochemistry, and Anticancer Potentials of African Medicinal Fruits: A Comprehensive Review

“…Leaves and branches extracts of this plant exhibited no cytotoxicity against HepG2 cells at the final concentration of 100 µg/mL [58], while another study showed antiproliferative activity of a methanolic branch extract with an LC 50 of 37 µg/mL, 72 µg/mL, 43 µg/mL, and 20 µg/mL against MCF-7, HCT-116, HepG2, and A-549, respectively [59]. A study showing the antioxidant effect of D. caffra fruit extract against free radicals showed that the whole fruit extract's DPPH scavenging action peaked at 52.11% (IC 50 95.09 µg/mL) at a concentration of 100 µg/mL, while the flesh extract's action was 27.11% (IC 50 187.12 µg/mL) at the same concentration. The two main phenolic compounds in dry fruits that were identified were chlorogenic, pyrogallol, and malic acids as the most prevalent organic acids.…”

“…Wild medlar has been utilized to treat roundworm, snake bites, malaria, fever, fungal infections (candidiasis), pneumonia, and chest-related problems in traditional medicine [ 56 , 88 , 92 ]. The successful use of wild medlar in traditional medicine can be traced back to its antioxidant, antibacterial, antifungal, antiplasmodial, and anti-inflammatory properties [ 88 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 ]. The cytotoxicity activities of methanolic and aqueous root extracts of this plant against MAGI CC5+ cells showed cytotoxic half-maximal concentrations (CC50) of 0.1 mg/mL [ 101 ].…”