Studies On Chemical Constituents Of Two Medicinal Species Of The Phyllanthus

The genus Phyllanthus,belonging to the family Euphorbiaceae,contains more than700 species worldwide,which are widely distributed in tropical and subtropical regions.There are about 30 species in China,that are mainly found in south of the Yangtze River.Many important species of the genus Phyllanthus have the effects of promoting diuresis,detoxifying,calming the liver,and clearing away heat,and are often used clinically for the treatment of dysentery,enteritis,urinary tract infections,and infectious hepatitis.Previous chemical literatures have shown that the genus Phyllanthus contains many structurally diverse components,including lignans,terpenoids,flavonoids,tannins,alkaloids,etc.,some of which exhibited antibacterial,antioxidant,anti-inflammatory and antiviral activities.As part of a programme continuously developing the genus Phyllanthus,we studied the chemical constituents of two medicinal plants P.reticulatus and P.flexuosus.As a result,thirteen compounds were isolated from the extract of P.reticulatus by column chromatography using D101 macroporous adsorbing resin,silica gel,ODS,Sephadex LH-20,etc.,and elucidated as 19-hydroxy cleistanthol 19-O-β-D-glucopyranoside（1）,phyllanthusmin G（2）,phyllanthusmin D（3）,phyllanthusmin C（4）,diphyllin 4-O-α-L-arabinopyranosyl-（1→3）-α-L-arabinopyranoside（5）,cleistanthol（6）,（-）-syringaresinol（7）,β-sitosterol-3-O-β-D-glucopyranoside（8）,friedelin（9）,stigmasterol（10）,dibutyl phthalate（11）,19-hydroxyspruceanol 19-O-β-D-glucopyranoside（12）,and reticulatuside B（13）.Four compounds were isolated from the P.flexuosus including spruceanol（14）,7-O-β-D-glucopyranosyljusticidin B（15）,ethyl 3,4-dihydroxybenzoate（16）and cleistanthol（6）.Of those isolates,19-hydroxy cleistanthol19-O-β-D-glucopyranoside（1）and phyllanthusmin G（2）are new compounds,compound 16 is isolated for the first time from the genus Phyllanthus,compounds 3,5,7,and 11 are isolated for the first time from the P.reticulatus,and compound 15 is isolated for the first time from the P.flexuosus.Furthermore,some compounds isolated from P.reticulatus were evaluated in vitro by CCK-8 assay.The results showed that compound 3 exhibited moderate cytotoxicities against HCT116,with IC₅₀ values of11.10μM,Compound 4 exhibited moderate cytotoxicities against A549,MCF-7 and HCT116,with IC₅₀ values of 18.64μM,13.58μM and 5.7μM,respectively.Compound 6 exhibited moderate cytotoxicities against cancer cells MDA-MB-231 and MCF-7,with IC₅₀ values of 21.56μM and 12.58μM,respectively.