Taxonomic Clarification on Turnera diffusa Ward and its Demarcation from “False Damiana” using Fluorescence, Scanning Electron Microscopy, HPTLC and UPLC
“Damiana” is used traditionally as stimulant, aphrodisiac, nerve tonic, diuretic, laxative, and for kidney, menstrual and pregnancy disorders . The ancient Mayans used it to treat giddiness and loss of balance  while the Mexican Indians made a beverage for its reputed aphrodisiac properties . Though “damiana” has a long history of usage, confusion over its precise identity and nomenclature still exists. According to British Herbal Pharmacopoeia (1996) “Damiana folium” consists of dried leaves of Turnera diffusa Willd. Ex Schults. var aphrodisica and related species. Beside “false damiana” are often used as substitutes for damiana. The name “false damiana” is referred to both T. ulmifolia (Turneraceae) as well as for Aplopapus disciodse DC (Asteraceae) . We observed that existing studies were not opportune and dependable in providing the exact identity of T. diffusa and discriminating it from the known “false damiana” species. In the present study we have provided taxonomic account on Turnera diffusa and furnished easy and reliable method to authenticate T. diffusa and to detect its possible substitute's using morphological and micro-morphological characteristics, with the aid of light, fluorescent and scanning electron microscopy. For the first time HPTLC, and UPLC comparative account has also been provided for the three species. These three methods in combination can be a useful tool in authentication of T. diffusa and for the detection of its adulterants. Acknowledgements: This research is funded in part by “Botanical Dietary Supplements: Science-Base for Authentication” funded by Food and Drug Administration grant number FD-U-002071–01. References:  Kumar S, et al. (2006) J of Medicinal Food, 9: 254–260.  Martinez M, (1944) Las Plantas medicinales de Mexico. Ediciones Botas. Mexico.  Lowry TP, (1984) Psychoactive Drugs, 16: 267–268.  Grieve M, (ed. Leyel, CF), (1996) A Modern Herbal, Barnes & Nobel, New York.