Phytochemical screening and antibacterial activities of Sorghum bicolor leaves derived from in vitro culture

Various research works recognized highly biological activities of sorghum vegetative portions which indicated the presence of bioactive compounds in their extracts. Considering environmental effects on the accumulation of secondary metabolites, this work aims to evaluate the antibacterial activity of sorghum using in vitro induced leaves as source for extract. In vitro shoot explants of sorghum used subcultured on Murashige and Skoog medium (MS) supplemented with 6-Benzyl adenine (BA) or Indole-3-butyric acid (IBA) at different concentrations (0.0–2.0 mg/L). The leaves induced in vitro were collected dried then macerated in ethanol for 4 hours. Phytochemical composition of the sorghum leaves extract was assessed using standard procedures. The crude extracts were evaluated for antibacterial activity using the agar well diffusion method. The significantly (P>0.05) maximum shoot length (5.7 cm) and the number of leaves (7.9 leaves) were obtained on MS medium supplemented with 2.0 mg/L IBA. The phytochemical composition of the leaves extract showed the presence of bioactive constituents including alkaloids, flavonoids, tannins, saponins and steroids and triterpenes. All the concentrations of the sorghum leaves extract showed variable antimicrobial activity against the studied bacteria strains with the strongest inhibitory effect reported (19.0 mm) against B. subtilis at the concentration of 100 mg/L. Our findings demonstrated that the in vitro leaves extract of sorghum possess a remarkable antibacterial activity. More research is needed on the characterization of bioactive ingredients of in vitro induced sorghum plants and their biological activities.