Abstract: Flavonoids are a class of phytochemicals, discovered in the 1930s, that generate pigment
in plants and play various biological roles in other cellular processes. It is estimated that the average dietary
intake of flavonoids in humans is several hundred mg per day. Quercetin and kaempferol, the most abundant
dietary flavonoids, has been reported for its strong antioxidant capabilities, anti-obesity and anti-inflammatory
activities. Therefore, a simple, reproducible, robust and precise high-performance thin layer chromatography
(HPTLC) densitometric method was developed and validated for the simultaneous estimation of quercetin
and kaempferol as per ICH guidelines. Quercetin and kaempferol were separated on aluminium-backed silica
gel 60 F254 plates using toluene: ethyl acetate: methanol: formic acid (5:3:1:0.2, % v/v) as the mobile phase.
This system was found to give compact bands of kaempferol and quercetin at Rf value 0.64 ± 0.05 and 0.69 ±
0.05, respectively. The proposed method was employed with a high degree of precision and accuracy for the
simultaneous estimation of quercetin and kaempferol in methanolic extracts of petals of Rosa damascena
Mill., whole plant of Origanum vulgare Linn., rhizomes of Nardostachys jatamansi DC., seeds of
Trachyspermum ammi Linn. and Apium graveolens Linn., and in-house Unani formulation Safoof-e-Muhazzil
containing these plants as ingredients.