Two flavonol glycosides; U1: naringenin-7-O-glucoside and U2: kaempferol-3-O-glucoside were isolated for the first time, from ethyl acetate fraction of the stem bark of a traditional medicinal plant called Uapaca heudelotti. IR and NMR spectroscopy were used to elucidate the structures of the isolated compound. The two compounds were active against the 7 tested microorganisms; Escherichia coli, Bacillus subtilis, Salmonella typhi, Streptococcus pyogenes, Klebsiella pneumoniae, Staphylococcus aureus and Proteus mirabilis. The zones of inhibition of the compounds ranged from 16 to 23 mm.The MIC value was as low as 6.25 μg/mL against Salmonella typhi, Streptococcus pyogenes, and Bacillus subtilis. The radical scavenging activity of compound U1 and U2 was 80 and 85 % at 240 μg/mL, while that of the standard drug was 98% at 240 μg/mL. The results show an existent possibility of using the plant for the treatment of microbial diseases.
Phaeophytin a, α-amyrin and lupeol isolated from Brachystelma togoense were screened against S. aureus, E. coli, S. pneumoniae, S. typhi, and C. albicans using Ciprofloxacin and Terbinafine as standards. The results showed that these phytochemicals displayed antimicrobial activity against the tested organisms with the zone of inhibition from 12 -27 mm. The result of minimum inhibitory concentration (MIC) showed that phaeophytin a was most active against C. albicans (0.09 mg/mL). The minimum bactericidal concentration (MBC) showed that phaeophytin a and lupeol were most active against S. aureus, S. pneumoniae and S. typhi (0.37 mg/mL). The result of minimum fungicidal concentration (MFC) showed that phaeophytin a was most active against C. albicans (0.1875 mg/mL).The activities of these phytoconstituents in B. togoense justified ethnomedicinal uses of the plant to treat various ailments.
The medicinal herb Brachystelma togoense schtlr (Apocynaceae) is used traditionally for treatment of ailments. The secondary metabolites, phaeophytin a, α-amyrin and lupeol were isolated from the CH2Cl2 and MeOH extracts of Brachystelma togoense. The structures were elucidated using 1H, 13C and 2D NMR. These phytochemicals have previously being reported to have various biological activities such as anti-inflammatory, anti-fungal and anti-cancer. The presence of phaeophytin a, α-amyrin and lupeol in Brachystelma togoense justified the use of the plant for medicinal purpose in Nigeria.
This research was undertaken to design several new antibiotics, by structurally modifying the C-9154 antibiotic, simultaneously improving its activity and lowering toxicity. This was achieved by synthesizing an analogue to the C-9154 antibiotic and seven derivatives of this analogue. The approach was to significantly reduce the polarity of the synthesized analogue in the derivatives to achieve increased permeability across cell membranes by conversion of the highly polar carboxylic group to an ester functional group. The compounds were fully characterized using infrared, GC-MS, and 1D and 2D NMR experiments. The in vitro biological activity of the compounds showed that the derivatives were more active than the analogue as was anticipated and both were more active than the standard drugs used for comparison. Work is ongoing to establish applications for the compounds as antiplasmodials, antivirals, anticancers/tumours, antitrypanosomiasis, anthelminthic, and as general antibiotics for human, veterinary, and even agricultural use as they had marked effect on both Gram-positive and Gram-negative bacteria and some fungi.
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