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2.24 Centella Species

      2.24.1 Ethnopharmacological Properties and Phytochemistry

      Centella asiatica (L.) Urban (syn. Hydrocotyle asiatica Linn.; Fam. – Umbelliferae) is naturalized throughout tropical and subtropical regions of India, Pakistan, Sri Lanka, Madagascar, and South Africa, as well as South Pacific and Eastern Europe. C. asiatica is a prostrate and aromatic and flourishes extensively in shady, marshy, damp wetlands (Tripathi et al. 2015). It is used for treatment of skin infections, healing of wounds, enhancement of nerves and brain cell activities, rheumatism, inflammation, syphilis, mental illness, epilepsy, hysteria, dehydration, and diarrhea (Jamil et al. 2007; Shanghai 1977; Yu et al. 2006). This species has been considered as a source of antioxidants (Singh et al. 2010; Subathra et al. 2005). The aerial parts of H. asiatica are used in the treatment of various ailments including body aches, headaches, insanity, asthma, leprosy, ulcers, and eczemas (Mishra 2003; Chaudhuri et al. 1978), as well as lupus, varicose ulcers, psoriasis, diarrhea, fever, amenorrhea, and diseases of the female genitourinary tract and also for relieving anxiety and improving cognition (Baily 1945; Gohil et al. 2010). Imipramine and total triterpenoids isolated from C. asiatica showed antidepressant activity (Chen et al. 2003). The aqueous extract demonstrated antinociceptive and anti-inflammatory against prostaglandin E2-induced paw edema in rats at different doses (Somchit et al. 2004; George et al. 2009), radioprotective (Shobi and Goel 2001; Sharma and Sharma 2002), and antiulcer activities (Cheng and Koo 2000; Cheng et al. 2004; Cho 1981), cognitive function and memory enhancement (Bradwejn et al. 2000; Dev et al. 2009; Tiwari et al. 2008; Wattanathorn et al. 2008), and increase in the dendritic length and dendritic branching points (Mohandas Rao et al. 2006). The in vivo studies have proved that whole extract as well as individual compounds of C. asiatica exhibited neuroprotective effects especially for Alzheimer's disease, Parkinson's disease, learning and memory enhancement, neurotoxicity and other mental illnesses such as depression and anxiety, and epilepsy (Bylka et al. 2014; Chandrika and Prasad Kumarab 2015; Lokanathan et al. 2016; Puttarak et al. 2017).

In addition to abovementioned properties, the C. asiatica also possessed a wide range of biological activities such as antipsoriatic (Sampson et al. 2001), hepatoprotective (Pingale 2008), anticonvulsant (Sudha et al. 2002), sedative (Wijeweera et al. 2006), immunostimulant (Wang et al. 2003), cardioprotective (Gnanapragasam et al. 2004; Raghavendra et al. 2009), antidiabetic (Venu Gopal Rao and Mastan 2007), cytotoxic and antitumor (Lee et al. 2002; Bunpo et al. 2004; Babu et al. 1995), antiviral (Yoosook et al. 2000), antibacterial (Zaidan et al. 2005), insecticidal (Senthilkumar et al. 2009), antifungal (Naz and Ahmad 2009; Ullah et al. 2009), antioxidant (Hamid et al. 2002; Jayashree et al. 2003; Bajpai et al. 2005; Pittella et al. 2009), and for venous deficiency (Pointel et al. 1987; Cesarone et al. 2001). Aqueous extracts of C. asiatica showed anti-psoriatic effects (Sampson et al. 2001). The 23-O-acetylmadecassoside, asiatic acid, madecassic acid, asiaticoside C, asiaticoside F, asiaticoside, madecassoside, and 23-O-acetylasiaticoside B with sitosterol 3-O-β-glucoside, stigmasterol 3-O-β-glucoside,