Phytochemical and biological investigation of leaf extracts of Phlomis crinita Cav. from northern Algeria

Phlomis crinita Cav., is a Lamiaceae very widespread in the North-West of Algeria (Chlef), but very little studied on the chemical and pharmacological levels; for this, a phytochemical screening, then a dosage of total phenolic compounds (TPC), total flavonoids (TFL) and condensed tannins (TCN) obtained by (02) methods (reflux and ultrasonic bath), followed by an evaluation of antibacterial activities and antioxidants, were carried out on (03) fractions: chloroform, ethyl acetate and n-butanol. The n-butanol extract (reflux) gives the best contents of total phenolic compounds (TTPC= 15.96 ± 0.09 ug Eq. Catechin / mg of extract), The acetate ethyl extract (reflux) gives the best contents of total flavonoids (TTFL = 33.98 ± 4.98 ug Eq. Rutin / mg of extract), and the chloroform extract (reflux) is richer on condensed tannins (TTCN= 757.67 ± 14.32 ug Eq. Catechin / mg of extract). The antibacterial activity of the extracts was slightly positive against Pseudomonas aeruginosa and Staphylococcus aureus. On the other hand, no antibacterial activity was observed against strains of Escherichia coli. The chloroform and n-butanol (reflux) extracts showed a strong ability to scavenge the DPPH radical comparable to that of ascorbic acid (IC50 Chloroform Ext. = 79.99 ± 1.48 ug/ml; IC50 n-Butanol Ext. = 94.96 ± 1.70 ug/ml and IC50 Ethyl Acetate Ext. = 588.68 ± 10.88 ug/ml versus IC50vit C = 55.26 ± 1.01 ug/ml)