Methods: Leaf of C. limon Linn was studied by macroscopical, microscopical, physicochemical, phytochemical, fluorescence analysis of powder of the plant and other methods for standardization recommended by WHO.

Results: T.S of leaf shows a layer of upper and lower epidermis covered with thick cuticle on both surfaces; the cells of upper epidermis are large in size and devoid of stomata while the cells of lower surface are comparatively very small with stomata present. T.S passing through the lamina showed two layers of palisade cells which extended up to the Meristem leaving 2-3 cells of collenchyma in between, spongy mesophyll 3-4 cells broad, lateral vascular bundles are abundant in lamina arranged in the middle of mesophyll tissue. T.S passing through meristem showed slightly protuberated upper surface while the lower surface deeply protuberated with a notch in the middle of the margin. Multilayered collenchymatous hypodermis was present towards the lower side while 2-3 cells on upper surface, Merisel showed a large sized median, collateral vascular bundle surrounded by fibrous bundle sheath. Phloem was arranged in arc shaped towards the lower side, numerous mucilage canals and cluster crystals of calcium oxalate were present in midrib and laminar region. Stomata: Paracytic Shape of epidermal cells: Irregular and collapse. The investigations also included leaf surface data; quantitative leaf microscopy and fluorescence analysis. Physiochemical parameters such as LOD, swelling index, extractive values and ash values were also determined. Preliminary phytochemical screening of leaf mainly revealed the presence of triterpenoids, saponins, tannins & flavonoids. Carbohydrates, proteins.

Conclusions: The results of the study can serve as a valuable source of information and provide suitable standards for identification of this plant material in future investigations and applications.