Pharmaceutical quality of Tiliae flos commercial samples: chemical composition - biological activity correlation

Abstract

Introduction. Tiliae flos represents flowers and bracts harvested from Tilia sp., well-known medicinal species widely used in traditional medicine. Sedative, immunomodulatory, antispasmodic and carminative properties represent the premises of usage also in modern therapy. Currently, most of the scientific data for linden chemical composition comes from Mexico, whereas Romanian endemic species have scarce studies. The main objective of the present study was to asses the pharmaceutical quality of five linden tea commercial samples according with Pharmacopoeial provisions. Also, we intended to prove a direct correlation between the chemical composition of the plant material and the biological properties. Material and methods. The samples were bought from different pharmacies from Iasi and they were given numbers from 1 to 5; samples 1 and 2 were packed as 50 g bags and 3-5 were sachets (1.5g) packages. In order to identify the plant species we started with macroscopic and microscopic analysis. To assess the chemical composition we extracted 5g of each sample with lOO mL of water and separately with ethanol 60 %. The lyophilized infusions and the dried alcoholic extracts were used for the phytochemical study. TLC and spectrophotometry means were used for the quantification of the active compound. The biological activity was expressed as DPPH scavenger potential. Results. From macroscopic point of view we noted important differences between the samples. TLC analysis revealed that there is a similar chemical spectra for all samples, with rutin and hyperoside as common compounds for all samples. Chlorogenic acid was present only in samples 3 and 4. The highest quantities of polyphenols were found for bulk samples 1 and 2. All sachets samples had lower quantities of polyphenols than the bulk, moreover sample 5 had the lowest value. In direct correlation to its chemical composition sample 2 had the best antioxidant potential. Also, from the same producer sample 4 (as sachets) had the second best activity, thus proving that the source of the plant material is important to obtain bioactive extracts. Conclusions. All in all, regarding Pharmacopoeial provisions some of the samples can't be identified macroscopically due to intensive grounding. Also the type of extract and the extraction methods influence greatly the final chemical composition and consequently the pharmacological activity. Therefore, the pharmacist should advice the patients in regards to how one can obtain the best extract useful for therapeutic purposes in their own home.