Asian Journal
Of Traditional Medicines

Abstract: There are four species of Morinda, namely, M. citrifolia L., M. elliptica Ridl., M. umbellata L., and M. coreia Ham. which are commonly found in Thailand. M. citrifolia is widely used as medicinal plant as an antinausea and antiemetic agent in Primary Health Care. Due to their relatively high degree of morphological variability and lack of information about Morinda spp., it was decided to carry out a series of microscopic and molecular analyses. The leaves were morphologically screened according to WHO Geneva guidelines, including leaf measurement, cross sectional midrib, stomatal measurement, and characterized by the mean values and standard deviation (SD) of the most important parameters. Molecular analysis was also performed by the Polymerase Chain Reaction/Restriction Fragment Length Polymorphisms (PCR/RFLP) method. The internal transcribed spacer (ITS) of the nuclear ribosomal RNA gene was amplified and the PCR products were digested using restriction enzymes. The result showed that the four investigated species of Morinda have the specific values of their leaf measurement index and stomata to allow them to be classified as the paracytic type. A dichotomous key can be generated based on the presence/absence of a calcium oxalate crystal structure, trichome, and fiber layer from the midrib cross section. The PCR/RFLP showed different patterns which can be used as a molecular marker to discriminate between the four investigated Morinda species. Using both microscopic and molecular analyses, we were able to authenticate the four investigated species of Morinda.

Key words: microscopic analysis, molecular analysis, Morinda species, leaf measurement, polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP), Internal Transcribed Spacer (ITS).