Asiaticosides

Chem Biodivers. 2012. The influence of certain taxonomic and environmental parameters on biomass production and triterpenoid content in the leaves of Centella asiatica from Madagascar. Rahajanirina V, Raoseta SO, Roger E, Razafindrazaka H, Pirotais S, Boucher M, Danthu P.SourceDépartement de Biologie et Ecologie végétales, Université d'Antananarivo, BP 906 Antananarivo, Madagascar.  Centella asiatica (Apiaceae family; Talapetraka in Malagasy) is a tropical and subtropical plant with leaves containing glycotriterpenoids (asiaticosides) used in traditional and modern medicine. C. asiatica is collected exclusively in natural stands. It is Madagascar's second most important indigenous plant export. The objective in this study is to provide data which will make it possible to optimize the harvest and thus effectively develop this resource. Two foliar morphotypes were identified: morphotype A with small reniform leaves (leaf area ca. 4.5 cm(2) ), found in the east of Madagascar, and morphotype B with large round leaves (up to 7.5 cm(2) ) found in the west, with sympatric zones in the central part of the island. Morphotype A produces a higher biomass, and is twice as rich in asiaticosides as morphotype B. Significant variations in biomass yield and asiaticoside content are observed depending on the date of collection: higher during the rainy season (December to April) and lower during the dry season (June to August). Inter-annual variations are also observed. Populations located at around 800-1400 m altitude on the eastern side of Madagascar, in a sub-humid climate, appeared to be more productive. These results provide more precise information to the economic sector, which confirms the empirical choices made by collectors. They represent the first elements towards sustainable management of the resource, and maybe even domestication.

Mycorrhiza. 2012. Induction of root colonization by Piriformospora indica leads to enhanced asiaticoside production in Centella asiatica. Division of Plant Molecular Biology, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India. Centella asiatica (Indian pennywort) has wide application in Indian and Chinese traditional medicines with documented evidence for wound healing and neuroprotective and anti-aging potential. Asiaticoside, a trisaccharide triterpene, is the most medicinally active compound in the plant. β-Amyrin synthase and squalene synthase have been identified as the two key genes in the triterpenoid pathway which regulate the production of asiaticoside in C. asiatica. The paper reports salient findings of our study utilizing the growth-promoting endophytic fungus Piriformospora indica to successfully colonize roots of C. asiatica in vitro cultures for investigating the effect of the mutualistic association on asiaticoside production. Co-cultivation of P. indica resulted in the rapid enhancement of root and shoot biomass of host plant, which was visible after 7 days of culture and continued up to 45 days. P. indica co-cultivation also favored the synthesis of asiaticosides, as evidenced by HPLC analysis which indicated about twofold increase (0.53% (w/w) in leaves and 0.23% (w/w) in whole plant) over control (0.33% (w/w) in leaves and 0.14% (w/w) in whole plant). Real-time PCR results confirmed the strong upregulation of squalene synthase and β-amyrin synthase transcripts in P. indica-challenged plants compared with the control. Our data demonstrate the potential use of P. indica as a means to enhance plant secondary metabolite production in planta with scope for further field evaluation.

Phytother Res. 1999.
Asiaticoside-induced elevation of antioxidant levels in healing wounds.
Shukla A, Rasik AM, Dhawan BN. Pharmacology Department, Central Drug Research Institute, Lucknow, India.
Asiaticoside derived from the plant Centella asiatica is known to possess good wound healing activity. Enhanced healing activity has been attributed to increased collagen formation and angiogenesis. Since antioxidants have been reported to play a significant role in the wound healing process we studied the effect of asiaticoside on the levels of certain antioxidants in the wound so as to explore the possible involvement of such a mechanism in the asiaticoside induced wound healing. Asiaticoside application (0.2%, topical) twice daily for 7 days to excision-type cutaneous wounds in rats led to increased enzymatic and non-enzymatic antioxidants, namely superoxide dismutase (35%), catalase (67%), glutathione peroxidase (49%), vitamin E (77%) and ascorbic acid (36%) in newly formed tissues. It also resulted in a several fold decrease in lipid peroxide levels (69%) as measured in terms of thiobarbituric acid reactive substance. However, continued application for 14 days showed no significant difference in these antioxidants compared with their values in vehicle treated wound tissue. It appears from the present study that asiaticosides enhanced induction of antioxidant levels at an initial stage of healing which may be an important contributory factor in the healing properties of this substance.