Sir,
Medicinal plants collected from wild are vulnerable to adulteration and substitution with other species or plant parts.[1] Centella asiatica (L.) Urban, commonly known as maṇḍūkaparṇĪ, is valued in Indian systems of medicine (ISM) for improving memory and for the treatment of nervine disorders. Several research workers have reported these biological activities of C. asiatica in various in vitro and in vivo test models. Commercial drugs of C. asiatica are frequently adulterated or substituted with other species.[2]
Centella asiatica is locally known as Vallarai in Tamil Nadu, where its sources of supply for the pharmaceutical industries of ISM are mainly from wild collection. The authors observed that the fresh plant materials in the name of Vallarai was sold in the farmers’ markets of Salem district, Tamil Nadu during the field study on medicinal plants and the sellers marketed the plant as a memory enhancer. Samples of the plant materials were collected from the farmers’ markets in different dates during April 2010 to March 2011, and they were identified with the help of local flora.[3] It was observed that the plant material sold in the name of Vallarai was not C. asiatica, and it was identified as Merremia emarginata (Burm. F.) Hall. F., a trailing herb with cordate leaves externally resembling C. asiatica [Figures 1-3]. The similar morphological characteristics of the leaves of both herbs with subtle differences make the substitution easy. The vernacular names of M. emarginata are Elikkathilai in Tamil and Ākhuparni in Sanskrit. The leaves of M. emarginata are consumable as pot-herb,[4] but in Salem district it is consumed in the name of Vallarai with the consumers expecting the benefits of C. asiatica.
Figure 1.
Vallarai – Centella asiatica
Figure 3.
Morphologically resembling leaves of Centella asiatica and Merremia emarginata
Figure 2.
Elikkathilai – Merremia emarginata
The magnitude of the problem increases, when M. emarginata is used in the place of C. asiatica in ISM pharmaceutical industries. The adulteration of C. asiatica in trade was earlier highlighted in the “Workshop on Standardization of Siddha drugs” held at Central Research Institute - Siddha, Chennai in 1996 and the problem was explained through the observation on the presence of small globose fruit capsules in loads of C. asiatica stored for industrial supply, which led to the suspicion about the adulteration, since the fruits of C. asiatica are compressed mericarps. Using this distinction, the plant material with small globose fruit capsules was identified as M. emarginata.[5]
The Raw Materials Herbarium and Museum, Delhi established by the Council of Scientific and Industrial Research also found the sample of the whole plant received in the name of C. asiatica was erroneous and established its identity as M. emarginata during the routine crude drug identification services.[1]
The observations show the importance of the standardization of herbal drugs at raw drugs level by utilizing the taxonomic and other scientific validation methods. Promoting cultivation of C. asiatica is the possible solution to ensure a steady supply of genuine plant materials.
ACKNOWLEDGMENT
Corresponding author is thankful to Central Council for Research in Siddha (CCRS), for the financial assistance provided under the Senior Research Fellowship (2009-2012). The authors are thankful to the Director I/c., CCRS for the financial help and encouragement.
REFERENCES
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