Phyllathus niruri L (Euphorbiaceae) is small annual, 30-60 high. PN has been used in Ayurvedic medicne for over 2000 years for a number of ailments including jaundice, gonorrhea, frequent menstruation, and diabetes and topically as a poultice for skin disorders. The plant has a role in liver disorders due to its febrifuge, antiseptic, astringent, stomachic and diuretic actions. It corrects gastrointestinal problems such as dyspepsia, colic, diarrhea, dysentery, and tones the GI tract back to function. PN primarily contains lignans (phyllanthine and hypophyllanthine), alkaloids, and flavonoids.

Hepatoprotection: Probably the most promising application of PN would be in treatment of hepatitis B. An aqueous extract of the plant was found to inhibit endogenous DNA polymerase of hepatitis B virus and binds to its surface antigen in vitro. The extract, non-toxic to mice, was tested for antiviral activity in woodchucks [liver disease including primary hepatocellular carcinoma induced by woodchuck hepatitis B virus (WHV) in woodchucks are very similar to those induced by hepatitis B virus (HBV) in humans]. In a trial using six long-term WHV carrier woodchucks, 5 treated animals showed a faster decrease in surface antigen titer compared to one untreated control. In animals recently infected with WHV, the extract was effective when administered i.p. in 3 out of 4 animals in reducing and within 3-6 weeks eliminating both the surface antigen titer and DNA polymerase activity in the serum. By inference, the extract should affect HVB infections in humans similarly.

Anti-HIV Activity: The alkaloids oh PN showed inhibiting effects on HIV replication in human cell lines. The effect was monitored in terms of inhibition of virus-induced cytopathogenecity in MT-4 cells. The selectvity index was 13.34 showing clear selective toxicity of the extract for the viral cells. Different workers have identified different chemical entities responsible for the anti-HIV activity.

In Urolithiasis: PN is used in Brazilian folk medicine for treatment of urolithiasis. A number of studies demonstrate the efficacy of PN for the treatment of urinary stones. An in vitro study on a model of calcium oxalate (CaOx) crystal endocytosis by canine kidney cells showed that an aqueous extract of PN was a potent and non-concentration-dependent inhibitor of CaOx crystal internalization. PN showed no toxicity, potentially increases calculus voiding in stone-forming patients.PN was also shown to inhibit endocytosis of CaOx crystals by MDCK cells. In a rat model of urolithiasis, it reduced calculus growth. In an in vitro study, CaOx precipitation was induced by addition of 0.1 N sodium oxalate to unfiltered human urine in the presence or absence of PN. The presence of PN extract did not inhibit CaOx precipitation, but PN prevented crystal aggregation and growth suggesting that PN may interfere at the early stages of stone formation.