Validated HPLC method for identification and quantification of p-hydroxy benzoic acid and agnuside in Vitex negundo and Vitex trifolia

A high performance liquid chromatography coupled with photodiode array detection method was developed for the identification and quantification of p-hydroxy benzoic acid and agnuside in the extracts of Vitex negundo and Vitex trifolia. The separation was achieved using acetonitrile and O-phosphoric acid–water (0.5%, v/v) as the mobile phase in an isocratic elution mode. Mean retention times of standard p-hydroxy benzoic acid and agnuside were 6.14 and 11.90 min respectively. The developed method was validated as per the ICH guidelines for limit of detection, limit of quantification, linearity, accuracy and precision. Good linearity (r²≥0.999) was observed for both the compounds in wide concentration range. Relative standard deviation values for intra-day and inter-day precision studies were less than 2%. The analytical recoveries of p-hydroxy benzoic acid and agnuside by the developed HPLC method were 93.07% and 106.11% respectively. Two compounds were identified and quantified in leaves and bar extracts of V. negundo and V. trifolia using the developed HPLC method.

Analysis of Flavonoids and Iridoids in Vitex Negundo by HPLC-PDA and Method Validation

The leaves of Vitex negundo have been reported to contain various bioactive constituents including iridoids and flavonoids. This is the first report on the simultaneous determination of iridoids and flavonoids by HPLC in three different samples of V. negundo leaves collected from three regions of India. Separation of iridoids and flavonoids was accomplished by HPLC and further elaborated for their quantification in V. negundo leaves using a C-18 column with detection at 254 and 330 nm, respectively. The developed HPLC method showed good linearity (r2≥0.999), high precision (RSD<5%) and a good recovery (99.3–103.0%) of the compounds. All the validation parameters of the developed HPLC were found to be within the permissible limits according to the ICH guidelines. The developed method was robust, accurate and reliable for the quality control of V. negundo leaves.

Validated HPTLC method for the simultaneous quantification of diterpenoids in Vitex trifolia L

Vitex trifolia L. is an important Indian medicinal plant with diverse pharmacological properties. In a recent study, we reported the isolation and antitubercular activity evaluation of three new diterpenoids from its leaves; here we have developed a validated rapid, simple, precise, and accurate high-performance TLC method for the simultaneous quantification of isolated diterpenoids in V. trifolia. Diterpenoids, 6α,7α-diacetoxy-13-hydroxy-8(9),14-labdadien (A), 13-hydroxy-5(10),14-halimadien-6-one (B), and 9-hydroxy-13(14)-labden-16,15-olide (C) were separated on silica gel 60F254 high-performance TLC plates using chloroform/acetone (98:2, v/v) as mobile phase. The quantitation of diterpenoids was carried out using densitometric reflection/absorption mode at 610 nm after postchromatographic derivatization using a vanillin/sulfuric acid reagent. A precise and accurate quantification can be performed for compounds A and B in the linear working concentration range of 333-1000 ng/band and for C in the range of 670-2000 ng/band with good correlations (r = 0.9984, 0.9991, and 0.9994, respectively). The method was validated for peak purity, precision, accuracy, robustness, LOD, and LOQ, as per the ICH guidelines. The method reported here is simple, reproducible and may be applied for the quantitative analysis of the above diterpenoids in the leaves of V. trifolia.

Validated high performance thin layer chromatographic method for simultaneous quantification of major iridoids in Vitex trifolia and their antioxidant studies

Negundoside (1), agnuside (2) and 6'-p-hydroxy benzoyl mussaenosidic acid (3) are known bioactive metabolites in Vitex trifolia. In the present study a simple precise and reproducible method was developed for simultaneous quantitation of NS (1), AS (2) and HMA (3) and the antioxidant capacity of above markers has also been determined. Marker compounds have been resolved using silica gel 60 F(254) plates, petroleum ether (60-80)/toluene/acetone/water (10:10:80:2 v/v/v/v) as the mobile phases. The method does not employ any derivatisation procedure and can be used as a quality control tool for routine analysis of drugs V. trifolia and V. negundo together with their commercial extracts. NS (1), AS (2) and HMA (3) showed significant activity in DPPH and NO radical scavenging assays.