Phytochemical investigation of Wikstroemia endemic species (Thymelaeaceae) from French Polynesia

International audienc

Phytochemical investigation of Wikstroemia endemic species (Thymelaeaceae) from French Polynesia

International audienc

Herbal medicine in the Marquesas Islands

Ethnopharmacological relevance: This manuscript reports data on medicinal plants used in Marquesas Islands traditional medicine. The subject is interesting due to the extreme geographical isolation of this archipelago and the scarcity of data on this subject. The hypothesis of the authors was that traditional knowledge in this area should be consequently largely preserved. The usual ethnobotanical collection of use/symptom was completed by an additional quantitative ethnobotany analysis providing two indices: the relative frequency of plant uses for a given affliction (RF) and the Informant Consensus Factor (ICF). Materials and methods: Our ethnopharmacological study was carried out between 2009 and 2012 in several parts of the archipelago by collecting the accurate names of the medicinal plants, their uses, the methods of preparation of the remedies and the associated traditional nosology. Two methods were applied: ex situ focus groups with scientists and local association partners, using fresh plant specimens, dried specimens, and photographs, guided by an outline of simple questions, and in situ semi-structured interviews of informants during walk in the woods or homegarden sampling. Results: 96 plant species were pointed out as medicine for which we collected 1774 use reports; 77 of these species cited by more than 1 informant are listed with their frequency of use. Three species account for one-third of use reports: Cocos nucifera (coconut), Gardenia taitensis (tiare Tahiti) and Microsorum grossum. Native species (either indigenous or endemic) represent only one quarter of all used species. The Polynesian introductions (plants introduced during Polynesian migrations) represent 42% of the Marquesan medicinal plants. On the other hand, one-third are modern introductions, introduced, for most of them, less than 200 years ago. Diseases are analyzed according to Marquesan concepts. In the present study, a special attention was focused on the descriptions of the local diseases. Their translation in French was discussed and verified in focus groups involving both scientists and Marquesan language specialists from the "Academie des Marquises". 40 plant species showed a high frequency of citation for a given affliction (RF >20). Despite the complex nosology the ICF to Marquesan traditional illness categories showed generally high ICF values, suggesting their strong coherence. Conclusions: An overview of the Marquesan pharmacopoeia, linked with ethnomedicinal practices, is presented in this paper. Marquesan traditional medicine survived until now despite the culture shock faced by the Marquesan population switching to numerous introduced plants commonly found in their close environment and easily gathered. Marquesan herbal medicine appears to draw its inspiration from a common Polynesian root. However further investigations on Marquesan nosologies are necessary to appreciate the originality of the Marquesan pharmacopoeia. Finally, the crossing of ICF and RF indices shows that 36 species have at least one significant use (frequencies > 20%) with high ICF value ( > 0.5). This suggests that some key phytochemica

Differential regulation of renal angiotensin-converting enzyme (ACE) and ACE2 during ACE inhibition and dietary sodium restriction in healthy rats

Angiotensin-converting enzyme (ACE) 2 is thought to counterbalance ACE by breakdown of angiotensin (Ang) II and formation of Ang(1-7). Both enzymes are highly expressed in the kidney, but reports on their regulation differ. To enhance our understanding of the regulation of renal ACE and ACE2, we investigated renal ACE and ACE2 expression during conditions of physiological (low-sodium diet) and pharmacological changes (ACE inhibition) in activity of the renin-angiotensin-aldosterone system (RAAS). Healthy rats were treated with vehicle or lisinopril with either a control or a low-sodium diet, and renal ACE2, ACE and plasma angiotensins were studied. During vehicle treatment, low sodium reduced renal ACE mRNA and activity without affecting ACE2 mRNA or activity and plasma Ang(1-7) and Ang II balance. Lisinopril significantly reduced renal ACE activity without affecting renal ACE2 activity. During ACE inhibition, low sodium reduced both ACE and ACE2 mRNA without affecting ACE2 activity or further reducing ACE activity. Measurements of renal neprilysin activity revealed no significant differences between any of the treatment groups. Plasma Ang(1-7) and Ang II balance is positively shifted towards the beneficial vasopeptide Ang(1-7) by the ACE inhibitor lisinopril, especially during a low sodium intake. In conclusion, modulation of the RAAS, by low sodium intake or ACE inhibition, does not affect renal ACE2 despite major variations in renal ACE. Thus, ACE and ACE2 are differentially regulated by low sodium and ACE inhibition. Therefore, we propose that the beneficial effects of ACE inhibitors are predominantly mediated by modulation of ACE and not ACE2. Whether this also applies to renal disease conditions should be investigated in future studies