Extraction and analysis of cosmetic active ingredients from an anti-cellulitis transdermal delivery system by high-performance liquid chromatography

Pharmacological Properties, Molecular Mechanisms, and Pharmaceutical Development of Asiatic Acid: A Pentacyclic Triterpenoid of Therapeutic Promise

Asiatic acid (AA) is a naturally occurring aglycone of ursane type pentacyclic triterpenoids. It is abundantly present in many edible and medicinal plants including Centella asiatica that is a reputed herb in many traditional medicine formulations for wound healing and neuropsychiatric diseases. AA possesses numerous pharmacological activities such as antioxidant and anti-inflammatory and regulates apoptosis that attributes its therapeutic effects in numerous diseases. AA showed potent antihypertensive, nootropic, neuroprotective, cardioprotective, antimicrobial, and antitumor activities in preclinical studies. In various in vitro and in vivo studies, AA found to affect many enzymes, receptors, growth factors, transcription factors, apoptotic proteins, and cell signaling cascades. This review aims to represent the available reports on therapeutic potential and the underlying pharmacological and molecular mechanisms of AA. The review also also discusses the challenges and prospects on the pharmaceutical development of AA such as pharmacokinetics, physicochemical properties, analysis and structural modifications, and drug delivery. AA showed favorable pharmacokinetics and found bioavailable following oral or interaperitoneal administration. The studies demonstrate the polypharmacological properties, therapeutic potential and molecular mechanisms of AA in numerous diseases. Taken together the evidences from available studies, AA appears one of the important multitargeted polypharmacological agents of natural origin for further pharmaceutical development and clinical application. Provided the favorable pharmacokinetics, safety, and efficacy, AA can be a promising agent or adjuvant along with currently used modern medicines with a pharmacological basis of its use in therapeutics.

Biopharmaceutical and pharmacokinetic characterization of asiatic acid in Centella asiatica as determined by a sensitive and robust HPLC-MS method

ETHNOPHARMACOLOGICAL RELEVANCE

Asiatic acid is one of the main components in the herb Centella asiatica, which is a well-known herbal medicine for its excellent pharmacological effects. To enhance the development potentials of asiatic acid as a chemopreventative agent, there is a great need to further understand its biopharmaceutical and pharmacokinetic properties. The aim of this research is to clarify the mechanisms of absorption and metabolism of asiatic acid, and explore its biopharmaceutical and pharmacokinetic properties in rats by using a sensitive and robust HPLC-MS method.

MATERIALS AND METHODS

Male Sprague-Dawley rats were randomly assigned to 2 groups and administered with asiatic acid by oral and intravenous administration. Plasma concentrations of asiatic acid were determined at designated points and main pharmacokinetic parameters were estimated. The absorption of asiatic acid was investigated by using Caco-2 cell line absorption model in vitro and rat intestinal perfusion model in situ. The metabolic rate of asiatic acid was investigated by incubating it in rat liver microsome system in vitro. In addition, the solubility of asiatic acid in aqueous solution was also determined by using HPLC-MS method.

RESULTS

The absolute oral bioavailability of asiatic acid is 16.25%. It was found that the permeability of asiatic acid is more than 10(-5) in the Caco-2 cell monolayer and rat intestinal perfusion model, and its main absorption region is the jejunum in rats. The metabolic rate of asiatic acid in rat liver microsomes, t1/2, is 9.493min, which shows that asiatic acid can be metabolized rapidly. The solubility of aisiatic acid was 0.1583mgmL(-1), and its poor solubility will result in low bioavailability.

CONCLUSIONS

The asiatic acid in a variety of matrixes was analyzed by using a sensitive and specific HPLC-MS method, and its absolute oral bioavailability in rats was very low. Asiatic acid can be metabolized rapidly in rat liver microsomes, and has good permeability across Caco-2 monolayer cell and rat intestine perfusion. It can be deduced that the low bioavailability of asiatic acid results from poor solubility and rapid metabolism.

Column-switching high-performance liquid chromatographic assay for determination of asiaticoside in rat plasma and bile with ultraviolet absorbance detection

A column-switching high-performance liquid chromatography (HPLC) method is described for the determination of asiaticoside in rat plasma and bile using column-switching and ultraviolet (UV) absorbance detection. Plasma was simply deproteinated with acetonitrile prior to injection and bile was directly injected onto the HPLC system consisting of a clean-up column, a concentrating column, and an analytical column, which were connected with two six-port switching valves. Detection of asiaticoside was accurate and repeatable, with a limit of quantification of 0.125 microg/ml in plasma and 1 microg/ml in bile. The calibration curves were linear in a concentration range of 0.125-2.5 microg/ml and 1-20 microg/ml for asiaticoside in rat plasma and bile, respectively. This method has been successfully applied to determine the level of asiaticoside in rat plasma and bile samples from pharmacokinetics and biliary excretion studies.