Biological and phytochemical screening of Erodium laciniatum and Lactuca orientalis
From ancient times, various herbal remedies and various medical agents containing flavonoids, tannins and phenols have been utilized for prevention and treatment of different diseases and disorders. Currently, such groups of bioactive compounds have become the subject of many antimicrobials researches, with possessed antiviral, antifungal and antibacterial activities. Moreover, many of high quality studies assessed the relationship between flavonoid's, tannin's and phenol's chemical structures and their antibacterial activities, and also studied their mechanisms of action on the microbial growth. These investigations approved that such classes of natural compounds can possess many therapeutic properties, including oestrogenic, antiinflammatory, enzyme inhibition and antimicrobial activities. In this study we aimed to screen Erodium laciniatum and Lactuca orientalis phytoconstituents and to evaluate their total flavonoids, tannins and phenols contents. An additional aim is to evaluate their antioxidant and antimicrobial activities. Phyto-constituents, total flavonoids, phenols and tannins were screened and evaluated by using standard analytical and phytochemical methods. Antioxidant activity was evaluated by using DPPH method meanwhile antibacterial activities were examined by using several reference bacterial strains obtained from the American Type Culture Collection (ATCC) and multidrug resistant clinical isolates. The tested strains included Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (MRSA Positive), Enterococcus faecium (ATCC 700221), Shigella sonnei (ATCC 25931), Enterobacter cloacae (clinical) and Klebsiella pneumoniae (clinical). In addition to that anti-fungal activities of these extracts were also examined against two reference strains Candida albicans (ATCC 90028) and Epidermatophyton floccosum (ATCC 52066). Antibacterial and antifungal activity of all prepared Erodium laciniatum and Lactuca orientalis organic and aqueous extracts were determined by using several methods including agar diffusion well-variant method, agar diffusion disc-variant method and broth micro-dilution method. The results of the phytochemical screening showed that L. orientalis and E. laciniatum contain phenols, tannins, flavonoids, saponins, monosaccharides, reducing sugars, carbohydrates, cardiac glycosides, and steroids, while alkaloids were not detected in both of the studied species. However, proteins, starch and terpenoids were not detected in L. orientalis and detected in E. laciniatum which means that E. laciniatum had more phyto-constituents than L. orientalis. Moreover, total flavonoid, tannins and phenols content in E. laciniatum extract were higher than the L. orientalis extracts. The IC50 values of the antioxidant activity were almost the same in L. orientalis and E. laciniatum extracts. Additionally the lowest value of MIC was for organic extract of E. laciniatum against Staphylococcus aureus. The same organic extract also showed to have the largest diameter of inhibition against Enterococcus faecium. However, L. orientalis aqueous extract showed to have the largest diameter of inhibition against Staphylococcus aureus. Whereas, the antifungal activity which was tested by using agar dilution method against Epidermatophyton floccosum showed that the organic extract of E. laciniatum had the lowest MIC which was 0.391mg/ml. In conclusion, both of the studied species have a mixture of phytochemicals and rich in flavonoids, phenols and tannins and have potential antioxidant and antimicrobial activities which can be used as therapeutic agents or can be used in cosmeceutical and pharmaceutical industries.