CHEMICAL CONSTITUENTS OF Sinningia mauroana AND SCREENING OF ITS EXTRACTS FOR ANTIMICROBIAL, ANTIOXIDANT AND CYTOTOXIC ACTIVITIES

Phytochemical study of aerial parts from Sinningia mauroana Chautems (Gesneriaceae) yielded 17 known compounds: sitosterol, stigmasterol, betulinic acid, oleanolic acid, hederagenin, maslinic acid, ursolic acid, pomolic acid, soranjidiol, methyl 4-hydroxyphenylacetate, 6-hydroxy-7-methoxy-α-dunnione, 7-hydroxy-6-methoxy-α-dunnione, jacaranone, calceolarioside A, conandroside, luteolin, and luteolin-7-O-glucoside. Complete NMR data of 6-hydroxy-7-methoxy-α-dunnione and 7-hydroxy-6-methoxy-α-dunnione were obtained in two different solvents. Hexane, ethyl acetate and ethanol extracts were screened for antimicrobial, antioxidant and cytotoxic activities. The antimicrobial activity was assayed against Staphylococcus aureus, S. epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, C. parapsilosis, C. dubliniensis, and C. glabrata, using the microdillution method. All extracts were inactive (MIC > 100 µg mL-1). The antioxidant activity was evaluated with the ORAC method; the ethyl acetate and ethanol extracts were active (TE relative > 800 µg g-1). The cytotoxic activity was tested against PC-3 (prostate) and SKMEL-103 (melanoma) human tumor cell lines, and 3T3 fibroblast cell line, using the MTT assay. The hexane extract showed strong activity against PC-3 and SKMEL-103 human tumor cell lines (IC50 < 0.25 and 3.07 µg mL-1, respectively), and a lower activity towards 3T3 fibroblasts (IC50 = 6.84 µg mL-1). The other extracts were inactive (IC50 > 50 µg mL-1).