PG-201

This prospective, randomized, double-blinded, double-dummy, multicenter study compared the efficacy and safety of PG201 (Layla®), a new product from extracts of 12 plant sources and SKI306X (Joins®) which have been well investigated and in relatively wide usage among herbal medicine, for the treatment of patients with knee osteoarthritis.

To compare the efficacy and safety of PG201 and SKI306X in patients with knee osteoarthritis.

A prospective, double-blinded multicenter study was conducted in 124 patients with Kellgren and Lawrence grade 2-3 knee osteoarthritis. Patients were randomly assigned to receive 600mg of PG201 (300mg, twice daily) and 600mg of SKI306X placebo (200mg, thrice daily) or 600mg of SKI306X (200mg, thrice daily) and PG201 placebo (300mg, twice daily) for 12 weeks. The primary outcome was the improvement of pain by week 8 as assessed by the 100-mm pain visual analog scale (VAS). Secondary outcomes included pain VAS improvement level at week 12, pain VAS improvement rate at weeks 8 and 12, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) improvement level at weeks 8 and 12, the improvement of the quality of life (EQ-5D), overall symptom self-assessment score, and rescue medication consumption.

The pain VAS improvement at 8 weeks was 14.2±16.2 in the experimental group and 11.9±13.1 in control group (p=0.557), confirming that the experimental group was not inferior to the control group as lower limit (-8.38) of 95% CI of the difference of VAS improvement between two groups was well above the allowed limit (-10 mm). There was no significant difference in all secondary outcomes including pain VAS, WOMAC, EQ-5D, overall symptom self-assessment score, and rescue medication consumption. Adverse events were low and similar between the two groups.

The results of this study showed that PG201 significantly reduced knee pain and improved knee function and were comparable to SKI306X. PG201 can be suggested as an effective treatment of knee osteoarthritis. Trial registration ClinicalTrials.gov:NCT01768468.

Fourteen compounds, coumarin (1), demethylsuberosin (2), xanthotoxin (3), psoralen (4), decursinol (5), decursin (6), decursinol angelate (7), chikusetsusaponin IVa (8), chikusetsusaponin IVa methyl ester (9), ethyl caffeate (10), syringaresinol (11), cnidilide (12), farnesol (13), and linoleic acid (14), were isolated from phytopharmaceutical PG201 (Layla(®)) by activity-guided fractionation utilizing inhibitory activity on nitric oxide (NO) production in vitro. The isolates 1-14 were evaluated for their inhibitory activity on LPS-induced NO and prostaglandin E2 (PGE2) productions in RAW 264.7 cells. All the compounds except 14 displayed suppressive effects on LPS-induced NO and PGE2 production with IC50 values ranging from 8 to 60 μM. Among these, compound 10 showed the most potent inhibitory effect on NO production from RAW 264.7 cells with an IC50 value of 8.25 μM. Compounds 2, 9, and 10 exhibited high inhibitory effects on PGE2 production with the IC50 values of 9.42, 7.51, and 6.49 μM, respectively. These findings suggest that compounds 2, 9, and 10 are the potential anti-inflammatory active constituents of PG201 and further study may be needed to explain their mechanism of action.