MORPHO-DIAGNOSIS OF Psidium guajava L., MYRTACEAE

Abstract

Psidium guajava L., commonly named as guava, is a shrub or small tree which belongs to the Myrtaceae family and is indigenous to tropical America. The leaves are used in folk medicine for treating diarrhea, dysentery and abdominal cramps. It has flavonoids, quercetin in particular, and antidiarrheic, antispasmodic, antimicrobial and anti-oxidant effects were confirmed. This study has analysed the foliar and caulinar anatomy of P. guajava, aiming to supply morpho-diagnostic information needed to quality control. The plant material was fixed, freehand sectioned and stained with astra blue and basic fuchsine. Microchemical tests were also conducted. The leaf is hypostomatic, presenting paracytic stomata, and has unicellular non-glandular trichomes. In the blade, it occurs uniseriate epidermis, parenchymatic sub-epidermal layers next to the adaxial surface and secretory cavities. The mesophyll is dorsiventral-like and the midrib and petiole are traversed by a bicollateral bundle encircled by a sclerenchymatic sheath. The stem shows continuous vascular cylinders of external phloem, xylem and internal phloem, traversed by narrow rays. Calcium oxalate crystals and cells containing phenolic compounds are seen in the leaf and stem. Keywords: Anatomy, flavonoids, guava, medicinal plant, pharmacognosy