A REVIEW ON HELIOTROPIUM INDICUM L. (BORAGINACEAE)

A REVIEW ON HELIOTROPIUM INDICUM L. (BORAGINACEAE)

G. K. Dash* and M. S. Abdullah

Faculty of Pharmacy & Health Sciences, Universiti Kuala Lumpur Royal College of Medicine Perak, 30450 Ipoh, Malaysia

ABSTRACT:Heliotropium indicum Linn., commonly known as ‘Indian heliotrope’ is very common in India with a long history of traditional medicinal uses in many countries in the world. The plant is reported to possess antibacterial, antitumor, uterine stimulant effect, antifertility, wound healing, anti-inflammatory, antinociceptive and diuretic activities. Several pyrrolizidine alkaloids have been isolated from this species. The active principle Indicine-N-oxide has reached Phase 1 clinical trials in advanced cancer patients.  But severe toxic side-effects showed that a therapy with indicine-N-oxide was not justified. Most of the alkaloids are hepatoxic and therefore internal use of Heliotropium species is not recommended. External application to promote wound healing and to fight infections seems to be less hazardous, but more research is needed. The comprehensive account of the chemical constituents and the biological activities are presented in this review such that the potential use of this plant in various traditional medicines can be systematically evaluated.

Keywords:

Heliotropium indicum Linn.,Traditional, Pyrrolizidine alkaloids, Bioactivity, Pharmacognosy

INTRODUCTION: The name "heliotrope" originates from the old idea that the inflorescence of these plants turned their rows of flowers to the sun. The meaning of ‘helios’ in Greek is ‘sun’ and ‘tropein’ from where the word ‘tropium’ is derived means ‘to turn’ ¹.

Heliotropium indicum Linn. (Fig. 1) belongs to family Boraginaceae. This family is well marked in their characteristics and not easily confused with any other.A majority of the plants in the family are herbs. Several heliotropes are popular garden plants and some others occur as weeds.

The genus Heliotropium comprises about 250 species and is distributed in tropical, subtropical and warm temperate zones of all continents ² but only a few species have been systematically investigated.

Heliotropium indicum Linn., commonly known as ‘Indian heliotrope’ is very common in India and some parts of Africa and Bangladesh, but also found in other countries. It is a coarse foetid herb, up to 2 ft. high, with ascending hirsuit branches found throughout India in sunny localities, on waste lands and anthropogenic habitats in periodically desiccating pools and ditches and anthropogenic habitats, generally below 800 m altitude, widely considered as a weed of fields. The leaves are simple, alternate or sub-opposite, 4.5 to 10 cm/2.5 to 5 cm, ovate or ovate oblong, margin undulate, sparsely strigose along nerves on either side, serulate or undulate with cordate, minutely pilose beneath nerves and veins conspicuous on the lower side.

H. indicum may flower throughout the year; the flowering season is very long and new flowers develop apically within the cyme while mature nutlets are already present at the base of the inflorescence. The flowers are white or violet coloured, regular, sessile, two ranked pentamerous, extra axillary. Sepals-5, 2.5 mm long, bristly with a few long hairs outside, free, green, linear lanceolate and unequal. Numerous branched, more or less densely hirsuit with spreading hairs are found in the stem and the root system is tap root and branched ^3-5.

FIG. 1: HELIOTROPIUM INDICUM LINN.

Ethnopharmacology: H. indicum has been used in different traditional and folklore systems of medicine for curing various diseases. An ethnopharma-cological survey revealed that, the traditional healers in Kancheepuram district of Tamil Nadu, India use H. indicum to cure skin diseases, poison bites, stomachache and nervous disorders ⁶.

In some African countries, another ethnopharma-cological survey reports that H. indicum is believed to be useful in treating malaria, abdominal pain and dermatitis. The highest number of usages (22%) was reported for the treatment of malaria ⁷. In Jamaica, the decoction of the entire plant is taken orally for treatment of intractable fever, ulcers, venereal diseases and sore throat and used externally in vaginal cavity to induce abortion in pregnant females and administered rectally to treat local sores in the rectum ⁸, while in Phillipines and Senegal, used orally as diuretic and for the treatment of kidney stone ^{9, 10}.

The infusion of the flower is taken orally by females for the treatment of menorrhagia in Jamaica ⁸. In Rodrigues, the decoction of the entire plant is used externally for treating herpes and the paste of fresh plant is used externally for cleansing and dressing of wounds and ulcers. The sap of the stem is used orally by females for treating dysmenorrhea ¹¹. The hot water extract of the flower is taken orally by the females as an emmenagouge in small dose and abortive in large dose while a paste of fresh entire plant is used externally for treatment of head lice in the West Indies ¹².

In Thailand, the dried inflorescence is believed to produce permanent sterilization when taken orally in females. One gram of the dried and powdered inflorescence mixed with milk or water is used for three days beginning with the fourth day of menses to achieve the desired result ¹³. Other folk remedies include use of decoction of the leaves for treatment of fever ¹⁴, insect bites, stings, diarrhoea, skin rashes, menstrual disorder and urticaria ¹⁵. The decoction of the leaves is also credited to be useful in curing insect stings (macerated with sugar cane juice), scorpion stings ¹⁰ and as abortive in large dose and emmenagouge in small dose ¹⁵.

The leaf paste is applied externally to cure rheumatism in Rayal Seema in Andhra Pradesh, India ¹⁶ and skin infection in Nicaragua ¹⁷. The decoction of both leaf and root together is also used for treating whooping cough in children in Eastern Nicaragua ¹⁸.In Amazon, the paste of both leaf and root together is applied externally in scorpion stings, bug bites ¹⁹ while the paste is recommended for treating sores and warts in Taiwan ²⁰.

In Malaysia, a paste made from the plant is applied to counteract putrefaction, to treat pyoderma and ringworm infection. In Burma, a decoction of the whole plant is used to treat gonorrhea while in Indonesia, an infusion of the leaves is used to soothe mouth sprue. A decoction of the dried roots is drunk in the Philippines to promote menses, while the seeds are used to treat cholera, malaria, and for wound-healing ²¹.

Phytochemistry: H. indicum is very rich in pyrrolizidine alkaloids (Fig. 2). Numerous pyrrolizidine alkaloids have been identified in this plant by several authors. The alkaloids reported in the entire plant include heliotrine ²², lasiocarpine ²², indicine ^{23, 24}, 12-acetyl indicine ²³, indicinine ²³, indicine-N-oxide ^24-26, retronecine ^{24, 27}, trachelan-thamide ²⁷ with traces of supinidine and lindelofidine ²⁷. The aerial parts contain echinatine, heleurine, lasiocarpine-N-oxide, supinine, heliotrine, indicine ^{23, 24, 28}, indicine-N-oxide ^{23, 24} and lasiocarpine ²⁸.

Presence of cynoglossine, europine-N-oxide, heleurine-N-Oxide, heliotridine-N-Oxide, heleotrine-N-Oxide ²⁹ and heliotrine ³⁰ have been identified from the seeds.

Other alkaloids such as putrescine, spermidine, homo spermidine and spermine have been identified in the leaves ³¹. Apart from alkaloids, several triterpenes and steroids including b-amyrin, lupeol ²², chalinasterol ³², b-sitosterol, stigmasterol and campesterol ³² have been reported from the entire plant. Other compounds reported from the entire plant include rapanone ³³ and hexacosan-1-ol ³². Presence of estradiol ³⁴ has been reported in the roots.

Helindicine, a new pyrrolizidine alkaloid together with the known lycopsamine were isolated from the roots of H. indicum. The structures were established by a combination of 1D and 2D NMR methods (COSY, HMQC, HMBC, and NOESY) and HREIMS. This is the first report of a lactone pyrrolizidine alkaloid in the genus Heliotropium. Helindicine and lycopsamine were assayed for antioxidant activity and showed moderate activity ³⁵.

The essential oil of H. indicum, extracted by hydrodistillation was analyzed by Gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). Aldehydes (52.8%) occurred in the highest amount represented by phenylacetaldehyde (22.2%), (E)-2-nonenal (8.3%) and (E, Z)-2-nonadienal (6.1%), with a significant quantity of hexahydrofarnesylacetone (8.4%) ³⁶. In another experiment, the volatile oil isolated by hydrodistillation was analysed by a combination of GC–FID and GC–MS. The major constituents of the volatile oil were phytol (49.1%), 1-dodecanol (6.4%) and β-linalool (3.0%) ³⁷.

FIG. 2: SOME IMPORTANT PYRROLIZIDINE ALKALOIDS OF H. INDICUM

Bioactivity: The volatile oil from the aerial parts isolated by hydrodistillation was studied for antituberculosis activity against Mycobacterium tuberculosis H37Ra in the Alamar blue assay system. The results revealed significant antituberculosis activity with an MIC of 20.8 µg/ml ³⁷. The antifungal activity ³⁸ of the aqueous extract of fresh leaves against Fusarium oxyparum and antibacterial activity ^{39, 40} of methanol extract against, Klebsiella spp., P. mirabilis, P. aeruginosa, S. aureus, B. subtilis and E. coli has been demonstrated. The methanol extract of the aerial parts of H. Indicum is reported to be active against S. aureus, S. pyogenes,  S. pneumonia,  K. pneumonia, E. coli and Shigella dysentriae respectively ⁴¹.

The petroleum ether extract of the entire plant is reported to possess significant antifertility activity when studied in rats ³². In another experiment, the n-hexane and benzene fractions of the ethanol extract of H. indicum were studied for antifertility activity in rats using anti-implantation and abortifacient models. In-vitro sperm motility study was also performed using different concentrations of the extract. The study revealed that H. indicum possesses promising abortifacient activity and moderate effects on implantation and sperm motility ⁴².

The antitumor activity of different extracts showed significant activity in several experimental tumor systems. The active principle was isolated and found to be N- oxide of the alkaloid, indicine ^{26, 43}. Indicine-N-oxide has reached Phase 1 clinical trials in advanced cancer patients.  In early clinical studies the possibility of using Indicine N-oxide for the treatment of leukemia and tumors was discussed ⁴⁴. But severe toxic side-effects showed that a therapy with indicine-N-oxide was not justified ^45-47. Most of the alkaloids are hepatoxic and therefore internal use of Heliotropium species is not recommended ⁴⁸.

The gastroprotective effects of the aqueous extracts of the dried leaves of H. indicum on indomethacin- induced gastric ulcerated mucosa has been demonstrated. The results showed normal morphological appearance of the different components of the mucosa layer indicating the aqueous extract possesses gastroprotective effects ^{49, 50}. The aqueous and ethanol extracts of the roots possess strong uterine stimulant effect when tested in rats ^{51, 52}.

The ethanol (95%) extract of the roots possess weak smooth muscle relaxant activity when tested on guinea pig ileum and rabbit duodenum ⁵². A studywas designed tofind receptors that possibly mediate the activity of H. indicum on smooth muscles. The effect of various concentrations of agonist drugs and an aqueous extract from the plant as well as the effects of these agonist drugs and the extract in the presence of specific reference antagonist drugs were established on isolated guinea-pig ileum, rabbit jejunum, rat uterus and rat anococcygeus preparations.

The extract caused dose-dependent contractions similar to the acetylcholine, methylcholine, carbamylcholine, nicotine, histamine and oxytocin used on the smooth muscle preparations studied. The contractions were significantly inhibited by atropine and hexamethonium, suggesting muscarinic and nicotinic activity, adrenaline and salbutamol, suggesting adrenoceptor activity and diclofenac sodium, suggesting the inhibition of synthesis and/or effect of products of cyclooxygenase such as prostaglandin. The extract was significantly stable to plasma cholinesterase. The receptor activity of H. indicum explains some of its traditional medicinal uses such as relieving abdominal pain, hypertension and impotence and sexual weakness ⁵³.

The wound healing activity of different extracts of H. indicum has been reported. Results revealed significant promotion of wound healing of the alcoholic extracts ^{54, 55}. In another experiment, six TLC fractions Sephadex LH-20, eluent : Methanol-water (6:4) from n-butranol extract of H. indicum were evaluated for their in vitro wound healing activity on H292 human lung cells using incision wound models in cell culture. Results of the study revealed better wound healing activity ⁵⁶.

The anti-inflammatory activity of different extracts of H. indicum has been reported using egg white ⁵⁷, carrageenin-induced acute paw edema model and cotton pellet granuloma subacute inflammation models ⁵⁸. The results showed that the extracts produced significant anti-inflammatory effect in both acute and subacute models of inflammation. The methanol extract of the dried roots of H. indicum was investigated for its possible antinociceptive, cytotoxic and diuretic activities in animal models. The extract produced significant writhing inhibition in acetic acid-induced writhing in mice.

The crude extract produced the most prominent cytotoxic activity against brine shrimp Artemia salina (LC₅₀ = 47.86 μg/ml and LC₉₀ =75.85 μg/ml). Moreover, diuretic activity was proven by the electrolyte loss ratio (Na+/K+ excretion ratio was 1.38 and 1.45 at the doses of 200 and 400 mg/kg respectively) as that of the standard diuretic furosemide (1.37) ⁵⁹. In another experiment, significant analgesic activity was observed with aqueous and ethanol extracts. However, a 14-day oral administration of 1-2g/kg of the extracts in Sprague-Dawley rats produced pathologic effects on the heart, kidney, liver and lungs. Therefore, although the aqueous and ethanol extracts have analgesic activity, it could have a cumulative toxic effects hence prolonged and continuous use is not advised ⁶⁰.

Pharmacognosy: A systematic pharmacognostical studies on the leaves of H. Indicum has been documented ⁶¹. The various physicochemical constants and preliminary phytochemical screening of the roots of H. indicum have been reported ⁶². Meher et al., 2011 ⁶³ reported the pharmacognostical studies on the stem.

Conclusion: H. indicum has it application in several traditional systems of medicine including Ayurveda and Siddha ^{64, 65}. For medicinal uses, H. indicum is exclusively collected from the wild. The plants are generally collected when fully grown. The plant contains a large number of pyrrolizidine alkaloids proved to be potent liver toxins.The toxicity of this plant has not been well studied. Heliotropium alkaloids have been considered as potential agents in chemotherapy and clinical trials have been executed. However, the applications in cancer therapy are limited by the toxic effects, in particular the hepatotoxic effect of the pyrrolizidine alkaloids content. External application to promote wound healing as an anti-infective requires more research.

REFERENCES:

4. Chittenden FJ:, The Royal Horticultural Society Dictionary of Gardening, Vol. II, Oxfordat Clarendon Press, Great Britain, 1951: 513-1088.
5. Gurib-Fakim A: Plant Resources of Tropical Africa 11(1): Medicinal plants 1, PROTA Foundation, Wageningen, Netherlands; 2008: 321-322.
6. Anonymous: The Wealth of India. Council of Scientific and Industrial Research, New Delhi, 1985: 29-30.
7. Kirtikar KR and Basu BD: Indian Medicinal Plants, Bishen Singh Mahendrapal Singh, Dehradun, 1994: 1685-1690.
8. Stewart R: Herbalism: Most common form of medicine available. The Eastern Pharmacist 1997; 47(5): 21.
9. Chellaiah M, Muniappan A, Nagappan R and Savarimuthu I: Medicinal plants used by traditional healers in Kancheepuram district of Tamil Nadu. Indian J Ethnobiol Ethnomed2006; 2: 43.
10. Togola A, Diallo D, Dembélé S, Barsett H and Paulsen BS: Ethnopharmacological survey of different uses of seven medicinal plants from Mali, (West Africa) in the regions Doila, Kolokani and Siby. J Ethnobiol Ethnomedicine2005; 1(1): 7.
11. Asprey GF and Thornton P: Medicinal plants of Jamaica, Part-III. West Indian Med J1955; 4(4): 69-82.
12. Quisumbing E: Medicinal Plants of Phillipines. Tech. Bull Phillipines, Dept. Agr. Nat resources, Manila, 16, Rep., 1951: 1.
13. Berhault J: Floore Illustree du Senegal. Govt. Senegal, Min Rural Development, Water and Forest Division, Dakar, Vol II, 1974: 110-114.
14. Gurib Fakim A, Swaeraj MD, Gueho J and Dulloo E: Medicinal plants of Rodrigues. Int J Pharmacog 2000; 34(1): 2-14.
15. Ayensu ES: Medicinal plants of the West Indies. J. Pharm. 1978; 1(2): 100.
16. Panthong A, Kanjanpothi D and Taylor WC: Ethnobotanical review of Medicinal plants from Thai traditional books, Part-I: Plants with antiinflamatory, antiasmatic and antihypertensive properties. J Ethnopharmacol1986; 18(3): 213-228.
17. Giron L, Freira V, Alonzo A and Caceres A: Ethnobotanical survey of Medicinal flora used by the Caribs of Guetmala. J Ethnopharmacol1991; 34(2/3): 173-187.
18. Duttagupta S and Dutta PC: Pharmacognostic study of the leaf of Heliotropium indicum. J Crude Drug Res1977; 15: 141.
19. Nagaraju N and Rao KN: A survey of plant crude drugs of Rayal Seema, A.P. India. J Ethnopharmacol 1990; 29(2): 137-158.
20. Barrett B: Medicinal plants of Nicaraguas Atlantic coast. Econ Bot1994; 48(1): 8-20.
21. Coee FG and Anderson GJ: Ethnobotany of the Garifuna of Eastern Nicaragua, Econ Bot1996; 50(1): 7l-107.
22. Duke JA: Amazonia Ethnobotanical Dictionary. CRC Press, Boca Raton FL. Peru, 1994: 181.
23. Lin CC and Kan WS: Medicinal plants used for the treatment of hepatitis in Taiwan. Amer J Chinese Med1990; 18(112): 35-43.
24. Wiart C:Medicinal Plants of the Asia-Pacific: Drugs for the Future? 2006, World Scientific Publishing Co. Pte. Ltd., Singapore.
25. Pandey DP, Singh JP, Roy R, Singh VP and Pandey VB: Constituents of Heliotropium indicum. Orient J Chem 1996; 12(3): 321-322.
26. Mattocks AR: Minor alkaloids of H. indicum. J Chem Soc1967; 329.
27. Mattocks AR, Schoental, R, Crowley, HC and Culvenor, CCJ: Indicine: The Major alkaloid of Heliotropium indicum L. J Chem Soc. 1961: 5400.
28. Dutta SK, Sanyal U and Chakraborty SK: A modified method of isolation of Indicine-N-Oxide from H.indicum and its antitumor activity against ehrlich ascites carcinoma and sarcoma-180. Indian J Cancer Chem1987; 9(2): 73-77.
29. Kugelman M, Liu WC, Axelrod M, Mc Bride TJ and Rao KV: Indicine-N-Oxide: The antitumor principle of Heliotropium indicum. Lloydia 1976; 39(2/3): 125.
30. Birecka N, Frohlich MW and Glickman LM: Amino alcohols of pyrolizidine alkaloid in Heliotropium species. Part-4. Free and esterified necines in Heliotropium species from Mexico and Texas. Phytochemistry 1983; 22(5): 1167-1171.
31. Hoque MS, Ghani, A and Rashid H: Alkaloids of Heliotropium indicum grown in Bangladesh. Pharm J1976; 5(3): 13.
32. Willaman JJ and Schubert BG: Alkaloid bearing plants and their contained alkaloids,                                  ARS, USDA, Tech Bull 1234, Supt Documents, Govt Print Off, Washington, 1961.
33. Pandey VB, Singh JP, Rao YV and Acharya SB: Isolation and pharmacological action of heliotrine, the major alkaloid of Heliotropium indicum seeds. Planta Med. 1982; 45: 229-233.
34. Birecka H, Dinolfo TE, Martin WB and Frolich MW: Polyamines and leaf senescence in pyrollizidine alkaloid bearing Heliotropium plants. Phytochemistry1984; 23(5): 991-997.
35. Andhiwal CK, Has C and Varshney RP: Chemical and Pharmacological studies of Heliotropium indicum. Indian Drugs 1985; 22(11): 567-569.
36. Mehta R, Arora OP and Mehta M: Chemical investigation of some Rajasthan desert plants. Indian J Chem. 1981; 20B : 834.
37. Mannan A and Ahmad K: Preliminary study of sex hormone of medicinal importance in Bangladeshi plants. Bangladesh Med Res Counc Bull1978; 4: 78-85.
38. Souza JSN: Pyrrolizidine alkaloids from Heliotropium indicum. J. Braz. Chem. Soc. 2005; 16(6B): 1410-1414.
39. Ogunbinu AO, Flamini G, Cioni PL, Adebayo MA and Ogunwande IA: Constituents of Cajanus cajan (L.) Millsp., Moringa oleifera Lam., Heliotropium indicum L. and Bidens pilosa L. from Nigeria.Nat Prod Commun 2009; 4(4): 573-578.
40. Theeraphan Machan, John Korth, Boonsom Liawruangrath, Saisunee Liawruangrath, Stephen G. Pyne Composition and antituberculosis activity of the volatile oil ofHeliotropium indicum Linn. growing in Phitsanulok, Thailand, Flavour and Fragrance Journal, 2006, 21(2),  265–267.
41. Singh J, Dubey AK and Tripathi NN: Antifungal activity of Mentha spicata. Int J Pharmacog 1994; 32(4): 314-319.
42. Das PK:Antibacterial activity of leaf extracts of Heliotropiun indicum Linn. Life sciences Leaflets 2011; 20: 904 –907.
43. Osungunna, MO and Adedeji KA: Phytochemical and antimicrobial screening of methanol extract of Heliotropium indicum leaf. Journal of Microbiology and Antimicrobials 2011; 3(8): 213-216.
44. Oluwatoyin SM, Illeogbulam NG and Joseph A: Phytochemical and antimicrobial studies on the aerial parts of Heliotropium indicum Linn. Annals of Biological Research 2011; 2 (2): 129-136.
45. Savadi RV, Alagawadi KR and Darade SS: Antifertility activity of ethanolic extract and its n-hexane and benzene fractions of Heliotropium indicum leaves on albino rats.Journal of Pharmacy Research 2009; 2(5): 927-930.
46. Perdue JRRE: KB Cell culture. I. Role in discovery of antitumor agents from higher plants. J Nat Prod 1982; 45(4): 418-426.
47. Ohnuma T, Sridhar KS, Ratner LH and Holland JF: Phase 1 study of indicine-N-oxide in patients with advanced cancer. Cancer Treat Rep. 1982; 66(7): 1509-1515.
48. Cook BA, Sinnhuber JR, Thomas PJ, Olson TA, Silverman TA, Jones R, Whitehead VM and Ruymann FB: Hepatic failure secondary to indicine N-oxide toxicity. A pediatric oncology group study. Cancer 1983; 52: 61–63.
49. Letendre L, Ludwig J, Perrault J, Smithson WA and Kovach JS: Hepatocellular toxicity during the treatment of refractory acute leukemia with indicine N-oxide. Cancer 1984; 54: 1256–1259.
50. Winton EF and McCue PA: Indicine N-oxide in the treatment of refractory adult actute leukemia. Cancer Treatment Rep 1986; 70: 933–934.
51. Roeder E and Wiedenfeld H: Pyrrolizidine alkaloids in plants used in the traditional medicine of Madagascar and the Mascarene islands. Pharmazie 2011; 66: 637–647.
52. Adelaja AA, Ayoola MD, Otulana JO, Akinola OB, Olayiwola A and Ejiwunmi AB:  Morphological gastroprotective effects of Heliotropiun indicum on gastric ulcerated mucosa. Pak J Pathol. 2006; 17(2): 60-64.
53. Adelaja AA, Ayoola MD, Otulana JO, Akinola OB, Olayiwola A and Ejiwunmi AB: Evaluation of the Histo-gastroprotective and antimicrobial activities of Heliotropium indicum Linn (Boraginaceae). Malaysian J Med Sci. 2008; 15(3): 22-30.
54. Barros GSG, Matos FJA, Vieira JEV, Sousa MP and Medeiros MC: Pharmacological screening of some Brazillian plants. J Pharm Pharmacol1970; 22: 116.
55. Vieira JEV, Barros GSG, Medeiros MC, Matos FGA and Souza MP: Pharmacological screening of plants of North East Brazil. II, Rev Brasil Farm 1968; 49: 67-75.
56. Koffuor GA, Boye A, Amoateng P, Ameyaw EO and Abaitey AK:Investigating the site of action of an aqueous extract of Heliotropium indicum Linn (Boraginaceae) on smooth muscles. Research Journal of Pharmacology 2012; 6(1): 12-19.
57. Reddy JS, Rao PR and Reddy MS: Wound healing effects of Heliotropium indicum, Plumbago zeylanicum and Acalypha indica in rats.J Ethnopharmacol 2002; 79(2): 249-251.
58. Dash GK and Murthy PN: Studies on wound healing activity of Heliotropium indicum Linn. leaves on rats. ISRN Pharmacology 2011; 1-8.
59. Dodehe Y, Barthelemy A, Calixte B, Jean David N, Allico Joseph D and Nelly F: In vitro wound healing effect of n-butanol fractions from H. indicum, Journal of Innovative Trends in Pharmaceutical Sciences 2011; 2 (1): 1-7.
60. Shalini S, Kaza R, Shaik F: Study on the anti-inflammatory activity of Heliotropium indicum. Journal of Innovative Trends in Pharmaceutical Sciences 2010; 1(1): 43.
61. Srinivas K: Anti-inflammatory activity of Heliotropium indicum Linn. and Leucas aspera Spreng. in albino rats.  Indian Journal of Pharmacology 2000; 32: 37-38.
62. Rahman MA, Mia MA and Shahid IZ: Pharmacological and phytochemical screen activities of roots of Heliotropium indicum Linn.Pharmacologyonline 2011;1: 185-192.
63. Boye A, Koffuor GA, Ameyaw EO and Abaitey AK: Analgesic activity and safety assessment of Heliotropium indicum Linn. (Boraginaceae) in rodents. International Journal of Pharmacology 2012; 8(2): 91-100.
64. Dattagupta S and Datta PC: Pharmacognostic study of the leaf of Heliotropium indicum Linn. (Boraginaceae). Pharmaceutical Biology 1977; 15(3): 141-151.
65. Sharma MK and Alexander A: Pharmacognostical and phytochemical investigations of roots of Heliotropium indicum Linn.  International Journal of Pharmaceutical Sciences and Research 2011; 2(6): 1569-1571.
66. Meher A, Panda SK, Agrahari AK, Pradhan AR and Bhoi R: Pharmacognostical and phytochemical evaluation of Heliotropium indicum L. Stem. Indian Journal of Novel Drug Delivery 2011; 3(4): 303-306.Anonymous: The Ayurvedic Pharmacopoeia of India, Part-I, Vol. VI, Ministry of Health and Family Welfare, Government of India, AYUSH, New Delhi, 2008: 66.
67. Wilson E, Rajamanickam GV, Vyas N, Agarwal A and Dubey GP: Herbs used in Siddha medicine for arthritis-A review. Indian Journal of Traditional Knowledge 2007; 6(4): 678-686.
    

    ---