The Encyclopedia Of Medicinal Plants

[Anais Wachowski]

Accordingto some estimates, as much as USD $10 billion is spent every year on alternative therapies. Over USDA $650 million is spent on botanical supplements that are used for chronic inflammatory diseases such as chronic obstructive airways disease (COPD), asthma, and rheumatoid arthritis. Botanical supplements have been used for centuries in traditional medicine, including Ayurveda (science of long life), Chinese medicine, Kampo (Japanese medicine), and Egyptian medicine. Several of the medicines that are traditionally used exhibit anti-inflammatory activities (Garodia et al. 2007; Aggarwal et al. 2006). Turmeric is one such herb.

In folk medicine, turmeric has been used in therapeutic preparations over the centuries in different parts of the world. In Ayurvedic practices, turmeric is thought to have many medicinal properties including strengthening the overall energy of the body, relieving gas, dispelling worms, improving digestion, regulating menstruation, dissolving gallstones, and relieving arthritis. Many South Asian countries use it as an antiseptic for cuts, burns, and bruises, and as an antibacterial agent. In Pakistan, it is used as an anti-inflammatory agent, and as a remedy for gastrointestinal discomfort associated with irritable bowel syndrome and other digestive disorders. In Pakistan and Afghanistan, turmeric is used to cleanse wounds and stimulate their recovery by applying it on a piece of burnt cloth that is placed over a wound. Indians use turmeric, in addition to its Ayurvedic applications, to purify blood and remedy skin conditions. Turmeric paste is used by women in some parts of India to remove superfluous hair. Turmeric paste is applied to the skin of the bride and groom before marriage in some parts of India, Bangladesh, and Pakistan, where it is believed to make the skin glow and keep harmful bacteria away from the body. Turmeric is currently used in the formulation of several sunscreens. Several multinational companies are involved in making face creams based on turmeric.

Although modern medicine has been routinely used in treatment of various diseases, it is less than 100 years old. Traditional medicine, in comparison, has served mankind for thousands of years, is quite safe and effective. The mechanism or the scientific basis of traditional medicine, however, is less well understood.

Numerous lines of evidence suggest that turmeric exhibits anti-inflammatory activity. In one study, crude organic extracts of turmeric were found to inhibit lipopolysaccharide (LPS)-induced production of tumor necrosis factor (TNF)-α (median inhibitory concentration [IC50] value = 15.2 μg/mL) and prostaglandin E2 (PGE2; IC50 value = 0.92 μg/mL) from HL-60 cells. A combination of several fractions that contained the turmeric oils was more effective than curcuminoids in inhibiting PGE2 production (Lantz et al. 2005). A hydroethanolic extract of turmeric was recently found to inhibit activation of human dendritic cells in response to inflammatory cytokines (Krasovsky et al. 2009).

The anticancer activities of turmeric include inhibiting cell proliferation and inducing apoptosis of cancer cells. Ar-turmerone, which is isolated from turmeric, induced apoptosis in human leukemia Molt 4B and HL-60 cells by fragmenting DNA to oligonucleosome-sized fragments, a known step in the process of apoptosis (Aratanechemuge et al. 2002). Moreover, the nucleosomal DNA fragmentation induced by ar-turmerone was associated with induction of Bax and p53 proteins, rather than B cell lymphoma 2 (Bcl-2) and p21, and activation of mitochondrial cytochrome c and caspase-3 (Lee 2009). This study showed that turmeric extract repressed the production and secretion of hepatitis B surface antigen from HepG 2.2.15 cells, an activity that is mediated through the enhancement of cellular accumulation of p53 protein by transactivating the transcription of the p53 gene as well as increasing the stability of the p53 protein (Kim et al. 2009).

Ethanolic turmeric extract was found to have opposing actions on murine lymphocytes and on Ehlrich ascitic carcinoma cells. Turmeric enhances lymphocyte viability and blastogenesis, but induces formation of cytoplasmic blebs and plasma membrane disintegration of tumor cells. Thus, it is suggested that turmeric is a conducive agent for lymphocytes and inhibitory as well as apoptosisinducing for tumor cells (Chakravarty and Yasmin 2005). A comparative study of edible plants like C. longa and F. caraica, and herbaceous plants like Gossypium barbadense and Ricinus communis extracts for their antitumor activities showed that the edible plant extracts exhibited higher antitumorigenic activities. Thus, edible plants that show in vivo antitumor activities may be recommended as safe sources of antitumor compounds (Amara, El-Masry, and Bogdady 2008).

Turmeric showed antioxidant potential by lowering oxidative stress in animals. A study showed that a diet containing 0.1% turmeric fed for 3 weeks to retinol-deficient rats lowered lipid peroxidation rates by 22.6% in liver, 24.1% in kidney, 18.0% in spleen, and 31.4% in brain (Kaul and Krishnakantha 1997). A study conducted on mice showed that turmeric extract inhibited membrane phospholipid peroxidation and increased liver lipid metabolism, which indicates turmeric extract has the ability to prevent the deposition of triacylglycerols in the liver. Dietary supplementation for one week (1% w/w of diet) with a turmeric extract showed lower phospholipids hydroperoxide level in mice red blood cells (RBC). The liver lipid peroxidizability induced with Fe2+/ascorbic acid was effectively suppressed by dietary supplementation with turmeric (Asai, Nakagawa, and Miyazawa 1999). Oral administration of a nutritional dose of turmeric extract decreased susceptibility to oxidation of erythrocyte and liver microsome membranes in vitro. When turmeric hydroalcoholic extract (1.66 mg/kg of body weight) was given to rabbits fed a high-fat diet, oxidation of erythrocyte membranes was found to be significantly lower than that in membranes of control animals. Levels of hydroperoxides and thiobarbituric acid-reactive substances in liver microsomes were also low (Mesa et al. 2003). Turmeric also seems beneficial in preventing diabetes-induced oxidative stress. In diabetic rats, an AIN93 diet containing 0.5% turmeric was found to control oxidative stress by inhibiting increases in thiobarbituric acid-reactive substances and protein carbonyls and reversing altered antioxidant enzyme activities without altering the hyperglycemic state (Arun and Nalini 2002; Suryanarayana et al. 2007). This diet also inhibited expression of vascular endothelial growth factor in diabetic rats (Mrudula et al. 2007). Further, it suppressed increase in blood glucose level in type 2 diabetic KK-Ay mice. A dose of 0.2 or 1.0 g of ethanol extract, 0.5 g of hexane extract, and 0.5 g of hexane-extraction residue per 100 g of diet in the mice feed suppressed significant increase in blood glucose levels. The ethanol extract of turmeric also stimulated human adipocyte differentiation, and it showed human peroxisome proliferator-activated receptor-gamma (PPAR-γ) ligand-binding activity (Nishiyama et al. 2005). Further, turmeric appeared to minimize osmotic stress. Most importantly, aggregation and insolubilization of lens proteins due to hyperglycemia was prevented by turmeric, indicating that it prevents or delays the development of cataracts (Suryanarayana et al. 2005).

Turmeric is also effective against neuronal, cardiac, and kidney disorders. The effect of turmeric on myocardial apoptosis and cardiac function was examined in an ischemia and reperfusion model of myocardial injury. Turmeric at 100 mg/kg administered for 1 month afforded significant cardioprotection and functional recovery that was attributed to reduction in cell death (Mohanty, Arya, and Gupta 2006).

Another interesting property of turmeric is its wound-healing ability. Gujral, Chowdhury, and Saxena (1953) found that turmeric has the property of healing wounds and ulcers in rats and rabbits. Other studies in rabbits revealed that stimulation of mucin secretion could protect the stomach from ulcer (Mukerji, Zaidi, and Singh 1961).

Besides causing these effects, addition of turmeric to the diet significantly improved weight gain of broiler chicks and reduced their relative liver weight. Turmeric also ameliorated the adverse effects of aflatoxin on some serum chemistry parameters (total protein, albumin, cholesterol, calcium) in broiler chicks and restored antioxidant functions in terms of level of peroxides, superoxide dismutase activity, and total antioxidant concentration in their livers (Gowda et al. 2008).

Turmeric acts as a digestive stimulant. As a dietary supplement, it favorably enhanced the activities of pancreatic lipase, chymotrypsin, and amylase. Moreover, turmeric mixed with other spices such as coriander, red chili, black pepper, and cumin brought about a pronounced stimulation of bile flow and bile acid secretion (Platel et al. 2002). Mukerji, Zaidi, and Singh (1961) showed that turmeric increases the mucin content of gastric juice in rabbits. Studies conducted by Farnsworth and Bunyapraphatsara (1992), Supniewski and Hano (1935), and Prucksunand et al. (2001) explain that turmeric has local anesthetic action. After eating turmeric, secretion of gastrin hormone from the antrum of the stomach may be inhibited. Turmeric may possess local membrane-anesthetizing activity at the antrum of the stomach, which then inhibits secretion of gastrin in the same way as oxethazaine, the active ingredient of strocain (Masuda 1973). This is the reason turmeric is administered before meals.

Turmeric has been tested against various diseases in humans (Table 13.5). In one study, the antimutagenic effects of turmeric were examined in 16 chronic smokers (Polasa et al. 1992). Turmeric was given in doses of 1.5 g/day for 30 days, and this was found to significantly reduce the urinary excretion of mutagens in these smokers. In six nonsmokers, on the other hand, no change in urinary excretion of mutagens was noted. These results suggest that dietary turmeric is an effective antimutagen and may be useful in chemoprevention. In another study, the effect of turmeric was examined on patients with irritable bowel syndrome. When 1 or 2 tablets of a standardized turmeric extract were given daily for 8 weeks, the prevalence of irritable bowel syndrome was significantly decreased, as was the abdominal pain/discomfort score (Bundy et al. 2004). Alcoholic extract of turmeric offered protection against BaP-induced increase in micronuclei in circulating lymphocytes of healthy individuals (Hastak et al. 1997). In a subsequent study, the authors treated patients suffering from oral submucous fibrosis (OSF) with turmeric extract (3 g/day) for 3 months. The number of micronuclei from oral exfoliated cells of OSF patients before and after treatment with turmeric extract was recorded. They found that the number of micronuclei in oral exfoliated cells decreased substantially and was comparable with that of normal, healthy individuals (Figure 13.3).

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