Picture

Figure 1 : C. asiatica. (a) Whole plant; (b) leaf; (c) root and rhizome; (d) stolon; (e) flower; (f) fruit. (Photos courtesy of Thiyagu, MARDI, 2012)

Definition

Pegaga herb consists of dried aerial part or whole plant of C. asiatica (L.) Urb.

Synonym (scientific name)

Centella coriacea Nannfd., Hydrocotyle asiatica L., Hydrocotyle lunata Lam., Trisanthus cochinchinensis Lour [1-4].

Vernacular name/ local name

Character (Color, Odor, Taste)

Identification:

• Plant Morphology
  A slender creeping herb with long-stalked leaf. The leaves are green, reniform, rounded apex and base deeply cordate stipulate with palmate netted veins and smooth texture; the petiole is relatively long, up to 20 cm. The flowers are in fascicled umbels with very small (about 4 mm) reddish petal and hermaphrodite; each flower bears 4-6 stamen and 2 styles. The fruit is small, mericarp in nature. The rootstock consists of rhizomes growing vertically down and stolon growing horizontally, interconnecting one plant to another [5].


• Microscopy
  The powder contains fragment of lamina consisting of upper epidermis with polygonal cells and underlying palisade cells that are rather small and closely packed. The lower epidermis has numerous paracytic stomata. Calcium oxalate prisms and macles are present. Fragments of parenchyma from the stolon and petiole are composed of longitudinal elongated cells. Fragments of bordered pitted vessel are also seen [5-8].
  
  
  
  
  (a)
  
  

  
  
  (b)
  
  

  
  
  (c)
  
  

  
  
  (d)
  
  

  
  
  (e)
  
  

  
  
  (f)
  
  
  Figure 2: Microscopic characters of C. asiatica herb powder. (a) Parenchyma cells with calcium oxalate macles (magnification 400X); (b) fragment of leaf epidermis with polyglonal cells (magnification 400X); (c) collenchyma cells with calcium oxalate macles (magnification 400X); (d) paracytic stomata (magnification 400X); (e) elongated parenchyma cells of the petiole (magnification 400X); (f) fragment of bordered pitted vessels.
  
• Color Test
  
  

  H2SO4 (conc.)	Dark brown
  5% NaOH	Light brown
  5% KOH	Light brown
  25% NH4OH	Yellow

Phytochemical Screening

Water extract of C. asiatica has been found to contain centellosides D-E, pectin and acidic arabinogalactan [9-11].

The ethanol extract had triterpenes (e.g. 2α,3β,20,23-tetrahydroxyurs-28-oic acid, 2α,3β,23-trihydroxyurs-20-en-28-oic acid), triterpenoid glycosides (e.g. asiaticoside, asiaticosides A-F, madecassoside, scheffuroside B) and a saponin (e.g. 2α,3β,23-trihydroxyurs-20-en-28-oic acid-O-α-L-rhamnopyranosyl-(1→4)-O-b-D-glucopyranosyl -(1→6)-O-β-D-glucopyranosyl ester) [12-15].

The methanol extract had triterpenes and triterpenoids (e.g. ursolic acid lactone, ursolic acid, pomolic acid, 2α,3α-dihydroxyurs-12-en-28-oic acid, 3-epimaslinic acid, corosolic acid, asiaticoside, madecassoside, asiatic acid, 6β-hydroxyasiatic acid, 3-O-[a-L-arabinopyranosyl]-2α,3β,6β,23-a-tetrahydroxyurs-12-ene-28-oic acid), a phenolic (e.g. rosmarinic acid), a steroid (e.g. b-sitosterol 3-O-b-glucopyranoside) and others (e.g. 8-acetoxy-1,9-pentadecadiene-4,6-diyn-3-ol, centellin, asiaticin, centellicin) [16-19]. Whereas the methanol-water extract had phenolics (e.g. castilliferol, castillicetin, isochlorogenic acid) [20].

C. asiatica has also been reported to contain brahmic acid, 3β-6β-23-trihydroxyolean-12-en-28-oic acid, 3β-6β-23-trihydroxyurs-12-en-28-oic acid, α-terpinene, thymol methyl ether, sceffoleoside A, bayogenin, centellasaponins B-D, centellose, D-gulonic acid, meso-inositol, docosyl ferulates) [21-25]. In addition, its cell cultures had irbic acid, chlorogenic acid and triferulic acid [26].

Medicinal uses

Uses described in folk medicine, not supported by experimental or clinical data: The C. asiatica plant is traditionally used for albinism, anemia, asthma, bronchitis, cellulite, cholera, constipation, dermatitis, diarrhea, dizziness, dysentery, dysmenorrhea, dysuria, epistaxis, epilepsy, haematemesis, hemorrhoids, hepatitis, hypertension, jaundice, leucorrhoea, nephritis, nervous disorders, neuralgia, measles, rheumatism, smallpox, syphilis, toothache, urethritis and varices. It is also used as an antipyretic, anti-inflammatory and a “brain tonic” [27-29]. Poultices of this plant have been used to treat contusions, closed fractures, sprains and furunculosis [29].

Dosage

Oral dose: 0.33-0.68 g or oral infusion of similar amount three times daily [4, 27-28].
Poultice: Apply to skin with wound, burns or inflammation after the fresh or dried whole plant is minced [30].
Juice: One handful of fresh whole plant made into fresh juice as tonic [30].

Storage

Store below 30°C. Protect from light and moisture.

Reference

1. Australian plant name index (APNI). [Internet]. Centella asiatica (L.) Urb; [cited 28 November 2012]. Available from: http://www.anbg.gov.au/cgi-bin/wintab.
2. African pharmacopoeia, 1st ed. Lagos, Organization of African Unity, Scientific, Technical & Research Commission.1985.
3. Vietnam materia medica. Hanoi, Ministry of Health. 1972.
4. Iwu MM. Handbook of African medicinal plants. Boca Raton, FL, CRC Press. 1993.
5. Malaysian herbal monograph ed. MHM. committee. Vol. 2. Kuala Lumpur. 2003;p.23.
6. Chinese-English manual of common-used in traditional Chinese medicine. China, Joint Publishing Co. & Guangdong Science & Technology. 1992;p.704.
7. The Ayurvedic pharmacopoeia of India. Part I. Vol. IV.[Internet] India, Government of India, Ministry of Health and Family Welfare; 2004; p.69. [cited on 9th December 2012]. Available from http://www.ayurveda.hu/api/API-Vol-4.pdf
8. Pharmacopoeia, British. “International edition.” HMSO Cambridge 1. 2009.
9. Weng XX, Zhang J, Gao W, Cheng L, Shao Y, Kong DY. Two new pentacyclic triterpenoids from Centella asiatica. Helvetica Chimica Acta. 2012;95:255-260.
10. Wang XS, Dong Q, Zuo JP, Fang JN. Structure and potential immunological activity of a pectin from Centella asiatica (L.) Urban. Carbohydrate Research. 2003;338:2393-2402.
11. Wang XS, Zheng Y, Zuo JP, Fang JN. Structural features of an immunoactive acidic arabinogalactan from Centella asiatica. Carbohydrate Polymers. 2005;59:281-288.
12. Yu QL, Duan HQ, Takaishi Y, Gao WY. A novel triterpene from Centella asiatica. Molecules. 2006;11:661-665.
13. Yu QL, Duan HQ, Gao WY, Takaishi Y. A new triterpene and a saponin from Centella asiatica. Chinese Chemical Letters. 2007;18:62-64.
14. Jiang ZY, Zhang XM, Zhou J, Chen JJ. New triterpenoid glycosides from Centella asiatica. Helvetica Chimica Acta. 2005;88:297-303.
15. Sahu NP, Roy SK, Mahato SB. Spectroscopic determination of structures of triterpenoid trisaccharides from Centella asiatica. Phytochemistry. 1989;28(10):2852-2854.
16. Thomas MT, Kurup R, Johnson AJ, Chandrika SP, Mathew PJ, Dan M, Baby S. Elite genotypes/chemotypes, with high contents of madecassoside and asiaticoside, from sixty accessions of Centella asiatica of South India and the Andaman Islands: for cultivation and utility in cosmetic and herbal drug applications. Industrial Crops Products. 2010;32:545-550.
17. Yoshida M, Fuchigami M, Nagao T, Okabe H, Matsunaga K, Takata J, Karube Y, Tsuchihashi R, Kinjo J, Mihashi K, Fujioka T. Antiproliferative constituents from Umbelliferae plants VII. Active triterpenes and rosmarinic acid from Centella asiatica. Biological & Pharmaceutical Bulletin. 2005;28(1):173-175.
18. Shukla YN, Srivastava R, Tripathi AK, Prajapati V. Characterization of an ursane triterpenoid from Centella asiatica with growth inhibitory activity against Spilarctia obliqua. Pharmaceutical Biology. 2000;38(4):262-267.
19. Siddiqui BS, Aslam H, Ali ST, Khan S, Begum S. Chemical constituents of Centella asiatica. Journal Asian Natural Product Research. 2007;9(4):407-414.
20. Subban R, Veerakumar A, Manimaran R, Hashim KM, Balachandran I. Two new flavonoids from Centella asiatica (Linn.). Journal of Natural Medicines. 2008;62:369-373.
21. Singh B, Rastogi RP. Chemical examination of Centella asiatica Linn – III: constitution of brahmic acid. Phytochemistry. 1968;7(8):1385-1393.
22. Singh B, Rastogi RP. A reinvestigation of the triterpenes of Centella asiatica. Phytochemistry. 1969;8(5):917-921.
23. Asakawa Y, Matsuda R, Takemoto T. Mono- and sesquiterpenoids from Hydrocotyle and Centella species. Phytochemistry. 1982;21(10):2590-2592.
24. Yu QL, Gao WY, Zhang YW, Teng J, Duan HQ. Studies on chemical constituents in herb of Centella asiatica. Zhongguo Zhong Yao Za Zhi. 2007;32(12):1182-1184.
25. Matsuda H, Morikawa T, Ueda H, Yoshikawa M. Medicinal foodstuffs. XXVII. Saponin constituents of gotu kola (2): structures of new ursane- and oleanane-type triterpene oligoglycosides, centellasaponins B, C, and D, from Centella asiatica cultivated in Sri Lanka. Chemical & Pharmaceutical Bulletin(Tokyo). 2001;49(10):1368-1371.
26. Antognoni F, Perellino NC, Crippa S, Toso RD, Danieli B, Minghetti A, Poli F, Pressi G. Irbic acid, a dicaffeoylquinic acid derivative from Centella asiatica cell cultures. Fitoterapia. 2011;82:950-954.
27. The Indian pharmaceutical codex. vol. I. indigenous drugs. New Delhi, Council of Scientific & Industrial Research. 1953.
28. British herbal pharmacopoeia, part 2. London, British Herbal Medicine Association. 1979.
29. Medicinal plants in Viet Nam. Manila, World Health Organization, WHO Regional Publications, Western Pacific Series, No.3.1990.
30. Standard of ASEAN herbal medicine. Volume 1. ASEAN countries. 1993;p.152.