Leptadenia hastata: A Review of its Traditional uses and its Pharmacological Activity

Leptadenia hastata (Pers.) Decne is often used traditionally for hypertension, catarrh, skin diseases, woundhealing, prostate complaints and as an aphrodisiac. In traditional systems of medicine, different parts are used including the leaves, latex, roots and even whole plant. Leptadenia hastata is reported to contain alkaloids, saponins, phenolic glycosides, tannins, flavonoids, proanthocyanidins and triterpenes. This review describes the medicinal properties, chemical constituents, and other important aspects of Leptadenia hastata. *Corresponding author: Steven D. Thomas, The Graduate School, Michigan State University, East Lansing, MI 48824, USA, Tel: 517-353-3262; Fax: 517-353-3355; E-mail: sdthomas25@gmail.com Received December 03, 2012; Accepted December 18, 2012; Published December 20, 2012 Citation: Thomas SD (2012) Leptadenia hastata: A Review of its Traditional uses and its Pharmacological Activity. Med chem 2:148-150. doi:10.4172/21610444.1000132 Copyright: © 2012 Thomas SD. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Introduction
Leptadenia hastata is edible non-domesticated vegetable and it is collected in wild throughout Africa. L. hastata is a voluble herb with creeping latex stems, glabescent leaves, glomerulus and racemus flowers as well as follicle fruits. It is typically grown in tropical dry lands in sandy soil. Wild foods like L. hastata provide food security during seasonal changes and are used medicinally in many areas. Vernacular names for L. hastata include: hagalhadjar (Arabic) in Chad, yadiya (Hausa) in Nigeria and Niger, hayla (Kusume) Ethiopia, ekamongo (Turkana) in Kenya, lolongo (Moore) in Burkina Faso, tarhat or darhat (Wolof), busumba amata (Jola) in Senegal, and nzongnè (Bambara) in Mali.

Traditional Uses
Decoction of the leaves of L. hastata with the bark of Erythrina senegalensis is either taken orally or used as a medicinal bath to treat onchocercosis in Mali [1]. In Chad, the roots are used to treat scabies [2]. This plant is commonly used in Hausa-speaking communities in Nigeria as a spice and used in sauces [3]. Also in Nigeria, local healers use the plant for hypertension, catarrh and skin diseases [4]. In Burkina Faso, locally it is used for sexual potency (chewing leaves), trypanosomosis (decoction of leaves), skin diseases and wound-healing (application of latex) [5]. In Senegal, the leaves have been reportedly used for lactation and as a purgative by Kerharo and Adam and Arbonnier [6,7]. Senegalese healers also use the L. hastata for prostate and rheumatism complaints [8].

Phytochemical Analysis and Nutritional Value
A phytochemical screening conducted by Bello et al. on L. hastata leaves indicate the presence of phenolic glycosides, tannins, flavonoids, proanthocyanidins, alkaloids and saponins [9]. The total phenolic, total flavonoid and proanthocyanidin contents were in the ranges of 17-38, 10-16 and 4-10 mg/g respectively depending on the extraction solvent.
In their study, they report that the acetone extract had highest content of total phenol (35.77 mg/g) than the methanol extract and aqueous extract. The flavonoids content of methanol fraction (15.85 mg/g) is higher than that of acetone and water extracts. The methanol extract (9.69 mg/g) had highest content of proanthocyanidins compared to water and acetone.

Antimicrobial activity
Aliero and Wara investigated the effect of L. hastata leaf extracts on Bacillus metagarium, Staphylococcus aureus, Escherichia coli, Salmonella paratyphi and Pseudomonas aeruginosa [15]. Aqueous extract markedly inhibited the growth of S. paratyphi and E. coli at 30 mg/ml and P. aeruginosa at 60 mg/ml. The activity exhibited by the methanol extract was generally low and acetone extract did not show any activity against the tested organisms.
Aliero and Wara [15] also examined in the same study the antifungal activity of L. hastata extracts with Aspergillus niger and Fusarium oxysporum. The result of their assays showed that methanol extract suppressed the growth of F. oxysporum and A. niger at 80 mg/ml with inhibition percentages ranging from 58.89 to 73.30%. The activity of acetone extract was lower with 40 and 50% inhibition respectively on the growth of A. niger and F. oxysporum.

Anti-androgenic activity
Bayala et al. demonstrated a competitive effect of the aqueous extracts of L. hastata leaf steams and the testosterone propionate (TP) on castrated immature Wistar rats [16]. They found that the anti-androgenic effect of the extract of L. hastata is expressed when the TP amounts are weak. Concentrations of TP ranged from 0.04-1,000 µg/ kg of TP. At low doses of TP, L. hastata (at 200 mg/kg) inhibited TP effects, whereas at high doses of TP, L. hastata extracts potentiated TP effects. To further evaluate the competition between TP and L. hastata extracts, Bayala et al. conducted a follow-up study [16]. In this 2012 experiment, L. hastata aqueous extracts reduced significantly the weight of androgen-dependent sex glands, the level of phosphatase acid prostatic (PAP) and fructose in seminal vesicles and prostate, and the serum testosterone level [17]. L. hastata extract concentrations ranged from 100-400 mg/kg. This study showed that the low doses of L. hastata increased TP activity and the high doses inhibited its action. These results confirmed the anti-androgenic effects of L. hastata extracts and have implications on prostate cancer treatment and reproductive health [18][19][20].

Anti-inflammatory activity
Nikiéma et al. examined triterpenes isolated from L. hastata latex for their anti-inflammatory activity. Lupeol, lupeol acetate and lupeol palmitate were found to be the main anti-inflammatory constituents in the croton oil-induced ear oedema test [21].
All the triterpenes tested at a dose of 0.42 µmol/ear induced a significant reduction of oedema. Lupeol exhibited 80% inhibition of oedema and was found to be more active than indomethacin (73%). Nikiéma also found that lupeol hemisuccinate, a synthetic derivative of lupeol exhibited a higher activity than lupeol, in the oedema test.

Wound-healing:
The results from the Nikiéma et al. [21] study verify the topical use of L. hastata latex in wound-healing. Their experiments examined an in vitro model of human skin keratinocytes (epidermal explants) cultured at an air-liquid interface on a deepidermized human dermis (DED) to investigate the effects of lupeol esters on skin repair.
Compared with the control, lupeol acetate and lupeol palmitate improved keratinocyte proliferation at a concentration of 5 µM in the culture medium. However, lupeol hemisuccinate induced a sufficient differentiation of keratinocytes with a well-formed stratum corneum without parakeratosis.

Anti-diabetic activity
The results of another Bello et al. study also demonstrated the potential of L. hastata extracts in diabetes mellitus management [22]. Their study, they evaluated the hypoglycaemic and hypolipidaemic effects of water and methanol extracts of the fresh leaves L. hastata in normal and alloxan-induced diabetic rat model. Rats were given 300 mg/kg body weight of plant extract per day in the morning hours for seven days. Oral administration of methanol and water extracts showed a significant decrease the blood glucose, while increasing liver and muscle glycogen levels. L. hastata extracts also reduced of serum triglyceride, VLDL (very low density lipoprotein) cholesterol levels and increased HDL (high density lipoprotein) cholesterol levels. Another indication of L. hastata, therapeutic effects was its α-glucosidase inhibitory properties [9]. Bello's results show that both the methanol and water extracts of L. hastata leaf significantly inhibited the activity of α-glucosidase.

Cytotoxicity
Aquino et al. [10] tested isolated compounds from the bark chloroform-methanol fractions for their cytotoxic activity on Raji cells (a human lymphoblastoid cell line from Burkitt's lymphoma).
However, their results shown no activity at concentrations evaluated (0.5 and 1.0 µg/ml) after six hours of incubation [10].

Toxicity and safety
Tamboura et al. [5] conducted their experiments by the means of male albino mice using concentrations 1000-2000 mg/kg body weight of L. hastata aqueous extract (leaves and stems). The mice were injected with the extract intraperitoneally and were observed during 48 to 72 hours. According to Tamboura et al., L. hastata is considered safe to use due to its high LD quotient value of 0.78 [5].

Conclusion
The review is an attempt to provide the ecological, phytochemical, ethnopharmacological, and pharmacological information on L. hastata, a wild vegetable used traditionally for culinary and medicinal purposes. The literature survey publicizes that L. hastata contains alkaloids, saponins phenolic glycosides, tannins, flavonoids, proanthocyanidins and triterpenes.
This vegetable shows antibacterial, antifungal, anti-inflammatory, anti-androgenic, anti-diabetic activities. There are many other traditional uses of L. hastata throughout Africa which serves as the basis for further studies. In addition to filling the gaps of food security, wild functional foods like L. hastata, deserve additional study and conservation efforts because of their role in local economies and health care treatments.