Abstract
The current study aimed to evaluate some biological activities of Saussurea costus (S. costus) such as phytochemical constituents, antimicrobial activity and antifeedant potential on the larvae of Spodoptera littoralis. The results revealed that the methanol extract of roots of S. costus are rich in some bioactive phytochemical compounds such as alkaloids, phenols/polyphenols, flavonoids, terpenoids, tannins, coumarins, quinines, steroids, cardiac glycosides and resins. The antimicrobial screening revealed that, among 12 referenced microbial strains (10 bacteria and 2 fungi), 4 Gram-positive bacteria exhibited high susceptibility with the methanol and ethanol extracts of S. costus, namely Bacillus cereus ATCC 10876 (IZ 16.0 +/- 0.0, 15.5 +/- 0.5 mm, MIC100, 50 mg/ml, MBC 200, 100 mg/ml), Staphylococcus saprophyticus ATCC 43867 (IZ 14.5 +/- 0.5, 15.5 +/- 0.5 mm, MIC50, 50 mg/ml, MBC100, 100 mg/ml), Staphylococcus epidermidis ATCC 12228 (IZ 13.5 +/- 0.5, 14.5 +/- 0.5mm, MIC50, 50 mg/ml, MBC 200, 100 mg/ml) and Staphylococcus aureus ATCC 29213 (IZ 11.0 +/- 0.0, 11.5 +/- 0.5 mm, MIC 100, 50 mg/ml, MBC 200, 100 mg/ml), respectively. Also, 1 fungal strain (Aspergillus niger ATCC 6275) revealed high susceptibility with the extracts (IZ 26.0 +/- 1.0 mm, MIC and MFC 50mg/ml). Other microorganisms recorded weak or no effect. Furthermore, the ethanolic extract of S. costus provided an anitfeedant effect toward Spodoptera littoralis larvae at different concentrations. In conclusion, the current findings provide evidence that roots of Saussurea costus is rich in bioactive phytochemical compounds and it might be a promising source of antimicrobial compounds as well as antifeedant activity against the larvae of Spodoptera littoralis.