Synergistic and antimicrobial effects of freshand dried extracts of red and green varieties of hibiscus sabdariffa calyxes on salmonella typhi and escherichia coli

Synergistic and antimicrobial effects of fresh and dried extracts of red and green varieties of Hibiscus sabdariffacalyxes on two enteric pathogens were investigated. Isolates of enteric pathogens namely: Salmonella typhi and Escherichia coli were obtained from Benue State University Teaching Hospital, Makurdi. Test organisms were subjected to confirmatory tests using standard methods of analysis. Samples of fresh and dried red and white calyxes of Hibiscus sabdariffa were purchased from Modern Market, Makurdi. Dried calyxes of the two varieties were washed, air dried at room temperature to a constant weight. The dried calyxes were converted to a powdered form using a blender. The powdered form was subjected to ethanolic extraction. Fresh calyxes of the two varieties were cleaned air dried and meshed using ethanol, it was allowed to evaporate in a water bath for 92 hours until a gummy concentrate was obtained. Phytochemical screening was carried out on the fresh and dried extracts of H. sabdariffa calyxes. Size of inoculum developed from isolates was calibrated using Mac Farland standard 1. Agar well diffusion method was used for susceptibility testing of the test organisms with ethanolic extracts of the dried red and green calyxes. Results of phytochemical screening of dried calyxes revealed that flavonoids was absent in the green variety but present in the red variety. Steroids, terpenoides and phlobatanins were absent in both varieties. Alkaloids, tanins and phenols were present in all varieties, Also phytochemical screening of (fresh) red and green calyxes extracts showed the presence of alkaloids, tannins and phenols as the bioactive components, saponins was absent in the fresh varieties of green and red. Although, flavonoid was also present in the (fresh) red variety but absent in the (fresh) green variety. Salmonella typhi recorded a zero activity with extract of dried green variety. The (fresh) green variety had zero activity against E.coli and inhibited Salmonella typhi at concentration of 40mg/ml. However, when a synergy was established between the two extracts (red to white) at ratio 25:25, diameter of zone of inhibition (9mm) was recorded with Salmonellatyphi as oppose to zero activity with extract of the green calyx alone. There was significant difference (p<0.05) in the effectiveness of the two varieties on test organisms. Statistical analysis also revealed that there was significant difference (p<0.05) in effectiveness between (fresh) red and (fresh) green varieties. Combining (dried) red and green ethanolic extracts of Hibiscus sabdariffa at different ratio revealed that there was no significant difference (p>0.05) between concentration and ratio of red to green variety on the growth of the tested organisms. Therefore, a combination of these two extracts in equal ratio can be recommended in the treatment of enteric diseases.