Antiuropathogenic and antioxidant activities of Hypoxis hemerocallidea Lam. extracts, and compounds from its taxonomically related species

Abstract

Hypoxis hemerocallidea Lam is one of the 43 Hypoxis species in South Africa, marketed extensively as over the counter herbal product for the management of several diseases. The plant commercial products link effi cacy to hypoxoside 4, its aglycone (rooperol), or β-sitosterol. This study investigated antibacterial and anti-oxidant activities of four other molecules and two extracts from the Hypoxis plant. Visual antioxidant limit of detection and free radical scavenging activities of test samples were determined using 20 mM hydrogen peroxide, 0.4 mM DPPH or ferric reducing antioxidant power assay. Quantitative free radical was determine by spectrophotometric method while antibacterial activity was evaluated using MICs against uropathogens: S. aureus (ATCC25923), S. marcescens (ATCC 14041), P. aeruginosa (ATCC 9721), P. mirabilis (ATCC 33583) and E. coli (ATCC 10536). Anti-oxidant activities visual limit of detection of 0.06 mg/mL and percentage free radical scavenging activity (IC 50 = 0.048-0.032 mg/ml) for pure compounds 1-4 and (IC 50 = 0.037-0.039 mg/ml) for extracts were obtained. The reducing power IC 50 ranged between 0.15-0.23 mg/ ml for extracts and 0.11-0.35 mg/ml for standards. Antibacterial potentials show a noteworthy to moderate MIC values of 0.20-1.56 mg/ml against S. aureus (ATCC 25923), S. marcescens (ATCC 14041), P. aeruginosa (ATCC 9721), P. mirabilis (ATCC 33583) and E. coli (ATCC 10536). Galpinoside 5, hemerocalloside 3 and curculigoside C 2 are the other active compounds in Hypoxis plant.