Isolation of Phytochemicals from Cordia rothii (Boraginaceae) and Evaluation of their Immunomodulatory Properties

 n -Hexane, EtOAc, and BuOH fractions obtained from methanol extract of leaves of Cordia rothii Roem and Schult, yielded 1-octacosanol (1), β-sitosterol (2), stigmast-5-en-3-O-β- D -glucoside (3), (2S,1′S,2′S,3′R,7′Z)-N-1′-(O-β- D -glucopyranosyl)methyl-2′,3′-dihydroxy-heptadec-7′-enyl-2-hydroxytetracosane-amide (4), methyl 2-hydroxy-3-(4′-hydroxy)-phenyl propionate (5), (2R)-(4-hydroxyphenyl)lactic acid (6), syringaresinol mono-β- D -glucoside (7), 6-hydroxy-3-oxo-α-ionol 9-O-β- D -glucopyranoside (8), staphylionoside D (9), and 3-(3′,5′-dimethoxy-4′-O-β- D -glucopyranosyl-phenyl)-prop-2E-en-1-ol (10). To the best of our knowledge, all compounds except 2 are reported for the first time from this source. Norterpenoid, lignan, cerebroside, and megastigmane are also reported for the first time. Immunomodulatory activity was evaluated using oxidative burst; phytohaemagglutinin (PHA) stimulated T-cell proliferation and nitric oxide (NO) assays. EtOAc fraction exhibited significant inhibitory activity against ROS with IC 50 value of 29.4 ± 2.8 µg/mL.
n-Hexane fraction exhibited very strong suppressive effect on PHA stimulated T-cell proliferation with IC 50 value of <3.12 µg/mL. Some of the sub-fractions also affected the adaptive immune system with >85% inhibition. Compound 7 exhibited significant inhibitory activity (IC 50 = 11.3 and 18.0 on PMN and whole blood respectively) on zymosan activated ROS generation. Eight sub-fractions showed potent inhibitory activity on the NO with >60% inhibition. These results suggest that compounds from C. rothii could be potential inhibitor for the mediators involved in innate and adaptive immune responses, and potential anti-inflammatory agents.