Characterization of Satureja khuzestanica leaf as a herbal medicine

Dried leaves of Satureja khuzestanica Jamzad are a popular herbal medicine and dental anesthetic among the nomadic inhabitants of southwestern Iran. The present study establishes criteria for identification of S. khuzestanica dried whole, fragmented and powdered leaves for specification as a herbal substance using macroscopic and microscopic characterization. Quantitative microscopy techniques were also considered. Macroscopically leaves exhibit a grayish-green color, are broadly ovate in shape with an acute apex, attenuate base, and ciliate margin and have a surface covered by an indumentum of glandular and non-glandular trichomes. Microscopically leaves have an isobilateral amphistomatic structure containing peltate glandular trichomes consisting of a multiseriate stalk (five cells) and an enlarged secretory head composed of 12 cells, capitate glandular trichomes of variable morphology together with two types of non-glandular trichomes. Oval-shaped hygromorphic diacytic stomata with an adaxial stomatal index of 13.54, collateral vascular bundles consisting of xylem, and three layers of sclerenchymatous tissue close to phloem together with cluster, prismatic and raphide calcium oxalate crystals were also identified as useful pharmacognostic parameters for identification of S. khuzestanica dried leaves.