Quantitative analysis of rutin, quercetin, naringenin, and gallic acid by validated RP- and NP-HPTLC methods for quality control of anti-HBV active extract of Guiera senegalensis

Context: Guiera senegalensis J.F. Gmel (Combretaceae) is a folk medicinal plant used in various metabolic and infectious diseases. In addition to its antiviral activities against herpes and fowlpox, the anti-HBV efficacy is very recently reported. Objective: To develop and validate simple, sensitive RP-/NP-HPTLC methods for quantitative determination of biomarkers rutin, quercetin, naringenin, and gallic acid in the anti-HBV active G. senegalensis leaves ethanol-extract. Materials and methods: RP-HPTLC (rutin & quercetin; phase-acetonitrile: water, 4: 6) and NP-HPTLC (naringenin & gallic acid; phase-toluene: ethyl acetate: formic acid, 6:4:0.8) were performed on glass-backed silica gel plates 60F(254)-RP18 and 60F(254), respectively. The methods were validated according to the ICH guidelines. Results: Well-separated and compact spots (R-f) of rutin (0.52 +/- 0.006), quercetin (0.23 +/- 0.005), naringenin (0.56 +/- 0.009) and gallic acid (0.28 +/- 0.006) were detected. The regression equations (Y) were 12.434x + 443.49, 10.08x + 216.85, 11.253x + 973.52 and 11.082x + 446.41 whereas the coefficient correlations (r(2)) were 0.997 +/- 0.0004, 0.9982 +/- 0.0001, 0.9974 +/- 0.0004 and 0.9981 +/- 0.0001, respectively. The linearity ranges (ng/spot) were 200-1400 (RP-HPTLC) and 100-1200 (NP-HPTLC). The LOD/LOQ(ng/band) were 33.03/100.1 (rutin), 9.67/29.31 (quercetin), 35.574/107.8 (naringenin), and 12.32/37.35 (gallic acid). Gallic acid (7.01 mu g/mg) was the most abundant biomarker compared to rutin (2.42 mu g/mg), quercetin (1.53 mu g/mg) and naringenin (0.14 mu g/mg) in the extract. Conclusion: The validated NP-/RP-HPTLC methods were simple, accurate, and sensitive for separating and quantifying antiviral biomarkers in G. senegalensis, and endorsed its anti-HBV activity. The developed methods could be further employed in the standardization and quality-control of herbal formulations.