Introduction
Natural products are an important source of new compounds leading to drugs in all major disease areas. They represent a pool of structures that have been optimized by evolution to interact with proteins and other molecules.1 The starting materials for about one-half of the medicines we use today come from natural sources. The future of higher plants as sources of medicinal agents for use in investigation, prevention and treatment of diseases is also very promising.2 Natural products have provided some of the important life-saving drugs used in the armamentarium of modern medicine. However, among the estimated 250,000-400,000 plant species, only 6% have been studied for biological activity and 15% have been investigated phytochemically. This illustrates the need for planned activity guided phyto-pharmacological evaluation of herbal drugs. This article aims to provide an overview of the chemical constituents present in various parts of Bombax ceiba and their ethnobotanical and pharmacological actions. It has been claimed in Ayurveda, that Bombax ceiba possesses proven medicinal properties and is the ingredient of many formulations.
Habitat and Distribution
Bombax ceiba Linnaeus belongs to the family Bombacaceae which contains about 26 genera and nearly 140 pantropical species.3 It is commonly known as Simbal, Simul, Indian kapok, Katsavar, Indian bombax or Red Silk cotton tree. It is widely found in temperate Asia, tropical Asia, Africa and Australia. In India, it can be found at altitudes upto 1500 m. In peninsular India, the tree is very common in the dry as well as moist deciduous forests and near rivers.The tree is a strong light-demander and fast growing. It grows best on deep sandy loams or other well-drained soils, particularly in valleys, in regions receiving 50 to 460 cm annual rainfall well distributed throughout the year.3
Morphology
Semal is a lofty, deciduous tree upto 40 m tall and 6 m or more in girth with horizontally spreading branches and young stems covered with stout, hard prickles. The bark is pale ash to silver grey in color. Flowers are large in diameter, red in color and numerous with copious nectar The fruits are brown capsule-like upto 15 mm long, filled with numerous black seeds which are irregular obovoid in shape, smooth and oily with dense silky hair. The fruit pulp is sweet and edible. Semal trees have compound leaves which are palmate in appearance. It is digitate, large, spreading, glabrous which has common petiole and the size of leaf is 15-30 cm long. The size of the leaflets varies from 10 cm to 20 cm. New leaves usually do not appear until flowering is over.4, 5
Ethanobotony
Abortifacient
Tribal people throughout India are well-acquainted with the knowledge of the plant’s usage. Preparation of about 30g of seed powder of B. ceiba and about 10 g Hing (Ferula foeitida) are used as an abortifacient by the Oraon tribe in West Bengal.6
Aphrodisiac, birth control, sexual diseases and tonic
An ethnobotanical survey of the tribal area of southern Rajasthan was carried out during the year 2001–2002 for ethnosexicological herbal medicines.7 B. ceiba was used as described: half a cup of ethanol extract of bark and flower was given for 3 days to both men and women with sexual diseases like hydrocele, leucorrhoea, gonorrhea and was also used to check menstrual disorders in women.7
Studies on the ethnomedicobotany of the Kandha tribe of Orissa showed that one teaspoon juice of fresh stem bark of B. ceiba, one teaspoon juice of fresh root of Asparagus racemosus, powder of seven black peppers (dried seed of Piper nigrum L., Piperaceae) and one teaspoon of processed sugar or gum taken orally on an empty stomach two times daily for 21 days to cure gonorrhoea, impotency, spermatorrhea, sterility, nocturnal emission and leucorrhoea. It is also prescribed for increasing sperm in semen and to act as aphrodisiac (Manu Vhokta).8 An ethnobotanical study has very often resulted in the discovery of important drug plants. An infusion of the bark of B. ceiba is used as a tonic.9
Anti-inflammatory activity
An ethnobotanical study of traditional anti-infllammatory plants used by the Lohit community of Arunachal Pradesh showed that fresh paste prepared from the bark of B. ceiba mixed with cow dung was applied over back muscle of leg at night to treat hotness and inflammation. 10
Muscular injury
An ethnobotanical study on medicinal plants around Mt Yinggeling, Hainan, China showed that B. ceiba barks and roots were used to treat muscular injury. 11
Wounds
Ethnomedicinal uses of useful plants from Mysore and Coorg districts, Karnataka included using the paste of B. ceiba bark externally for cattle wounds. 12
Anti-diarrheal
Field observations recorded on the use of medicinal plants in traditional health care systems of the Tharus of three villages in Nawalparasi district of central Nepal has shown that bark juice of B. ceiba was applied locally for the treatment of wounds;. 13 The bark juice was mixed with the bark juice of Magnifera indica and P. guajava and drunk to cure dysentery and intestinal spasm. The resin was also taken orally to treat worms and diarrhea; root juice was consumed to treat abdominal pain and gonorrhea. 13
The native people of state Mizoram used traditional methods of treatment based on herbal drugs. Decoction of the leaves of B. ceiba and the bark of Mangifera indica was taken (5 ml, 2-3 times daily) orally to treat diarrhea. 14 An ethnobotanical survey of anti-diarrheal plants of the Parinche valley, Pune district, Maharashtra 15 showed that the root bark of B. ceiba was peeled with a sharp knife and the inner white portion was crushed and made into a fine paste. The paste was then added to 30–50 ml of water and administered in the morning, preferably on an empty stomach for 2 days to treat diarrhea. 15
Leprosy
An ethnobotanical survey of medicinal plants used by traditional practitioners and religious healers of Bangladesh has shown that seeds and roots of B. ceiba were used in the treatment of leprosy. 16
Pimples and skin disease
The ethnopharmacology of medicinal plants among the tribal communities of North-West Frontier Province, Pakistan showed applications of B. ceiba in the treatment of skin diseases and in folk cosmetics. Fresh bark of B. ceiba was crushed and applied topically on pimples, carbuncles and boils. 17
An ethnomedicinal claim of some distinctive medicinal plants utilized by Pawara tribal in the Satpuda hills of Maharashtra showed that concentrated bark decoction of B. ceiba were applied in the treatment of skin diseases and pimples. Bark powder of B. ceiba was boiled with water and given orally twice a day for 7 days to treat leucorrhoea. 18
Pharmacology
Hypotensive activity
Shamimin along with lupeol [lup-20 (29) en-3b-ol], which possesses potent hypotensive activity, have been isolated from B. ceiba stem bark. BCBMM [filtrate from BCBM (Methanolic extract of defatted stem bark)] one of the most active fractions has revealed its adverse effects on heart, liver and kidneys of mice at the dose of 1000 mg/kg/d. 19
Antioxidant activity
The antioxidant activity of a methanolic extract of B. ceiba was evaluated using several antioxidant assays, in terms of its: (i) ability to scavenge DPPH (1, 1-diphenyl-2-picryl-hydrazyl) and hydroxyl free radicals; (ii) action against lipid peroxidation (in rat liver microsomes and soy bean phosphatidylcholine liposomes), induced by ascorbyl radicals and peroxynitrite; and (iii) effect on myeloperoxidase activity. 20 The cytotoxicity was monitored through the mitochondrial activity in the Vero cell line. The extract showed antioxidant activity in all assays. The EC (50) for DPPH was 87 µg/ml; lipid peroxidation of microsomes and soy bean liposomes induced by ascorbyl radicals were 141 µg/ml and 105 µg/ml, respectively, and by peroxynitrite were 115 µg/ml and 77 µg/ml, respectively. The K (0.5) value for myeloperoxidase activity inhibition by the extract was 264 µg/ml. The extract showed very low toxicity toward Vero cells.20 The total phenolic content present in water extracts of B. ceiba (ela imbul; gum), was determined by Folin-Ciocalteu method. Caffeine and gallic acid were quantified by high performance liquids chromatography (HPLC). Total free radical scavenging activity of each ingredient was investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and the values were compared with phenolic and gallic acid present in each plant. The polyphenol content of B. ceiba were 32.57 ± 5.04% of total extractable. Detectable levels of gallic acid were present only in B. ceiba (1.46 mg/g of total extractable). The EC50 values for DPPH radical scavenging activity for B. ceiba were 15.47 ± 1.80 µg cm-3, The mean values of EC50 (y) for DPPH radical scavenging activity were correlated with total phenolics (x) present in plant extracts (y = -35.417x + 1428; R = 0.9887). 21
Antiangiogenic activity
A methanol extract of the stem barks of B. ceiba was found to exhibit a significant antiangiogenic activity on in vitro tube formation of human umbilical venous endothelial cells (HUVEC). Bioactivity-guided fractionation and isolation carried out on this extract identified lupeol as an active principle. At 50 and 30 µg/ml, lupeol showed a marked inhibitory activity on HUVEC tube formation while it did not affect the growth of tumor cell lines such as SK-MEL-2, A549 and B16-F10 melanoma.
Hypotensive and hypoglycaemic activity
Shamimin, a C-flavonol glucoside from B. ceiba leaves showed significant potency as a hypotensive agent at the doses of 15 mg/kg, 3 mg/kg, 1 mg/kg and significant hypoglycaemic activity at 500 mg/kg in Sprague Dawley rats.
Antimicrobial and antibacterial activity
Plant extracts (methanol and aqueous) were assayed for their activity against multi-drug resistant Salmonella typhii. Strong antibacterial activity was shown by the methanol extracts of Salmalia malabarica.
Plant or plant parts were collected, dried, homogenized and extracted in two organic solvents viz. methanol and acetone. The antibacterial activity against Klebsiella pneumoniae was done by agar disc diffusion method. The activity was compared with standard antimicrobials Amikacin and Piperacillin.
Cytotoxicity
Aqueous extracts of the plants were screened for their cytotoxicity using the brine shrimp lethality test. The present study supports that brine shrimp bioassay is simple reliable and convenient method for assessment of bioactivity of medicinal plants and lends support for their use in traditional medicine.
Hepatoprotective activity
The hepatoprotective activity of a methanolic extract of flowers of B. ceiba (MEBC) was investigated against hepatotoxicity produced by administering a combination of two anti-tubercular drugs isoniazid (INH) and rifampicin (RIF) for 10 and 21 days by intraperitoneal route in rats. MEBC were administered at three graded dose i.e. 150, 300 and 450 mg/kg i.p. 45 min prior to anti-tubercular challenge for 10 and 21 days. MEBC was evident in all doses as there was a significant decrease in alkaline phosphatase (ALP), alanine transaminases (ALT), aspartate transaminases (AST) and total bilirubin levels, but increase in the level of total protein in comparison to control. MEBC significantly decreased the level of TBARS (thiobarbituric acid reactive substances) and elevated the level of GSH (reduced glutathione) at all doses as compared to control. The results obtained from the analysis of biochemical parameters and histopathological studies, resulted in the conclusion that the MEBC were not able to completely revert the hepatic injury induced by INH and RIF, but it could limit the effect of INH and RIF to the extent of necrosis.
Aphrodisiac
The aphrodisiac activity of B. ceiba root extract was investigated. The extract (400 mg/kg body wt/day) was administered orally by gavage for 28 days. Mount latency (ML), intromission latency (IL), ejaculation latency (EL), mounting frequency (MF), intromission frequency (IF), ejaculation frequency (EF) and post-ejaculatory interval (PEI) were the parameters observed before and during the sexual behavior study at day 0, 7, 14, 21, and 28 days. The extract reduced significantly ML, IL, EL and PEI (p < 0.05). The extract also increased significantly MF, IF and EF (p < 0.05). These effects were observed in sexually active and inactive male mice.
Conclusion
An extensive literature survey has revealed that B. ceiba has a long history of traditional use for a wide range of diseases. Much of the traditional uses have been validated by scientific research. It is an important species that has economic and ecological importance and should be conserved for ecological perspectives. The plant is used in dysentery, menorrhagia, skin troubles, haemorrhoids, for the treatment of snake bite and scorpion sting, boils, leucorrhoea, internal bleeding, calculus affections, chronic inflammation, ulceration of bladder and kidney, gonorrhea, haemoptysis, influenza, enteritis, pulmonary tuberculosis, cystitis and catarrahal affections bleeding piles. The pharmacological and clinical studies reported in the present review confirm the therapeutic value of B. ceiba. The presence of interesting/novel chemical compounds indicates that the plant could serve as “lead” for development of novel agents in disorders in the coming years. In this regard, further studies need to be carried out to explore B. ceiba for its potential in preventing and treating diseases.
