Antioxidant Potential of Dried Enicostemma littorale
November 23, 2011; Accepted: November 24, 2011;
Published: November 30, 2011
Medicinal plants act as alternative source of disease treatment due to which
their use is increasing day by day. These plants are mostly herbaceous and are
used to treat various human ailments; either solely or in combination with other
plants (Odhiambo et al., 2011; Karim
et al., 2011; Sohail et al., 2011).
For this, generally leaves and roots are harvested, which are processed as concoction
and decoction. Enicostemma littorale is one of the important medicinal
herbs and one of its important attributes includes antitumor activity (Kavimani
and Manisenthlkumar, 2000). Its methanolic extracts protected the albino
mice from Dalton's ascitic lymphoma and promoted the growth of peritoneal (membrane
lining the abdominal cavity) cells. Its methanolic extracts also have antiulcer
activity, as they protected the rat from aspirin, ethanol and pyloric ligation-induced
gastric ulcers (Roy et al., 2010). These extracts
maintain the pH levels of gastric tract and showed the anti-inflammatory effects;
moreover these extracts were able to inhibit the albumin denaturation. Its other
uses are due to its anti-diabetic, antioxidant property; it increases serum
insulin levels of diabetic rat and improves antioxidant level in oxidatively
stressed rats (Gopal and Udayakumar, 2008; Maroo
et al., 2003). It modulates the levels of reduced glutathione, catalase
etc. and inhibits the lipid peroxidation. This plant has many important traditional
medicinal uses also; it was used to treat diabetes, insect bites, itching, swelling,
ulcer, peritoneal and joints problems (Abirami and Gomathinayagam,
2011). This may be due to its phytochemical (alkaloids, phenols, flavonoids,
sterols etc.) and mineral (calcium, silica, phosphate, iron etc.) profile. But
competent use of medicinal plants and their products is often suffered by the
contamination of fungus, which produces several toxic compounds like fumonisin
and aflatoxin (Katerere et al., 2008). This can
severely affect human health and in Africa 15 out of 16 tested herbal products
are contaminated with fungus (majorly with Aspergillus, Fusarium and
Penicillium). This contamination was the result of poor storage and transport
conditions. Thus reliable and durable storage method is essentially required
to stop the contamination of herbal product. Drying is one of the usually used
storage techniques; it reduces the chances of plants product contamination with
microbes (Elrashid and Iqbal, 2000; Muller
and Heindl, 2006). But drying temperature, air and humidity can affect the
products quality and quantity; moreover these conditions are plant specific.
Therefore to facilitate the storage of E. littorale the estimation of
drying techniques effect would help in finding correct drying conditions.
Sthishkumar et al. (2009) studied the efficiencies
of different drying methods (sun, shade and oven) in preserving the antioxidant
properties of E. littorale. According to them drying brought a significant
loss in total phenolic (antioxidant) contents of plant extracts and they judged
it against methanolic, distilled and boiled distilled water extracts. These
three extracts of fresh plant parts showed relatively high concentration of
phenols and maximum concentration of these antioxidant compounds were obtained
from the boiled water extracts. Thus boiling offered a good opportunity of phenolic
compounds extraction from fresh samples with a significantly higher (2.15 mg
g-1) concentration of phenols. But when plants were subjected to
drying some changes occurred due to loss of moisture and altered activity of
enzymes, which reduced the phenols concentration in them. As phenolic contents
obtained from shade drying technique were 1.82 in methanol, 1.77 in distilled
and 1.95 mg g-1 phenols in boiled water extracts. On the other hand
phenols of sun dried plant were 1.93, 1.54 and 1.91 mg g-1 in methanol,
distilled water and boiled water extracts, respectively. While minimum concentration
were obtained from the oven dried extracts, hence the availability of phenolic
compounds was drying and extraction technique dependant variable. But extracts
DPPH (2, 2-diphenyl-1-picrylhydrazyl) antioxidant activity was not determined
by the concentration of these phenols and maximum antioxidant activity was observed
in oven dried methanolic extracts. Its value was 89.362 mg Ascorbic Acid (AA)
g-1 followed by sun dried extracts (76.579 mg AA g-1),
while the maximum antioxidant property of fresh methanolic extracts was only
10.99 mg AA g-1. On the other hand when these extracts were subjected
to FRAP (Ferric Reducing Antioxidant Power) test, a direct proportionality was
observed in fresh, shade dry and oven dried extracts phenolic compounds
and ferric ion reduction. Their antioxidant activity was increased with increasing
phenol concentration; however there was a difference in phenols concentration
and relative antioxidant property of sun dried plants. As their methanolic extracts
were with maximum phenols (1.93 mg g-1) but their ferric reduction
activity was less than distilled and boiled distilled water extracts. Hence
the antioxidant potential of E. littorale was influenced by drying and
extraction method, which was due to difference in drying method efficiencies
and possible enzymatic changes. As oven drying provided more intense heat than
sun and shade drying techniques, which more strongly caused a decrease in heat
unstable compounds and inactivated the polyphenol oxidase. It might also cause
some chemical conversion of compounds, which produced other compounds with more
strong antioxidative property. As oven dried methanolic extracts were depleted
with phenolic compounds but showed highest antioxidative potential. Since this
can be said that oven drying technique was good for preserving DPPH antioxidants,
while sun dried technique was efficient for preserving ferric reducing agents.
E. littorale remained an important part of traditional medicines and
its extracts could be used to reduce oxidative stress, diabetes, cancer ulcer
etc. Thus the development of storage technique for its long time preservation
will assist its use at required time. For this purpose Sthishkumar
et al. (2009) studied the effect of drying technique on antioxidants
of E. littorale. According to their results drying techniques differentially
affects the concentration of antioxidative agents and their relative antioxidative
property. But, a further detailed investigation of E. littorale phytochemicals
is necessary to understand the role of drying technique in storing its medicinal
properties. This will help in economical use of dried plants products.
Abirami, P. and M. Gomathinayagam, 2011. A review on Enicostemma littorale. Pharmacologyonline, 1: 75-83.
Direct Link |
Elrashid, A.A. and N. Iqbal, 2000. Dehydration characteristics of sweet cherries (Prunus avium L.). Pak. J. Biol. Sci., 3: 231-235.
CrossRef | Direct Link |
Gopal, R. and R. Udayakumar, 2008. Enzymatic and non-enzymatic antioxidant activities of Enicostemma littorale in p-DAB induced hepatocarcinoma in rats. Int. J. Pharmacol., 4: 369-375.
CrossRef | Direct Link |
Karim, A., M.N. Sohail, S. Munir and S. Sattar, 2011. Pharmacology and phytochemistry of Pakistani herbs and herbal drugs used for treatment of diabetes. Int. J. Pharmacol., 7: 419-439.
Katerere, D.R., S. Stockenstrom, K.M. Thembo, J.P. Rheeder, G.S. Shephard and H.F. Vismer 2008. A preliminary survey of mycological and fumonisin and aflatoxin contamination of African traditional herbal medicines sold in South Africa. Hum. Exp. Toxicol., 27: 793-798.
Kavimani, S. and K.T. Manisenthkumar, 2000. Effect of methanolic extract of Enicostemma littorale on Dalton's ascitic lymphoma. J. Ethnopharmacol., 71: 349-352.
CrossRef | PubMed |
Maroo, J., A. Ghosh, R. Mathur, V.T. Vasu and S. Gupta, 2003. Antidiabetic efficacy of Enicostemma littorale methanol extract in alloxan-induced diabetic rats. Pharm. Biol., 41: 388-391.
Direct Link |
Muller, J. and A. Heindl, 2006. Drying of Medicinal Plants. In: Medicinal and Aromatic Plants, Bogers, R.J., L.E. Cracker and D. Lange (Eds.). Springer, Netherland, pp: 237-252.
Odhiambo, J.A., C.W. Lukhoba and S.F. Dossaji, 2011. Evaluation of herbs as potential drugs/medicines. Afr. J. Tradit. Complementary Altern. Med., Vol. 8. 10.4314/ajtcam.v8i5S.20
Roy, S.P., C.M. Niranjan, T.M. Jyothi, M.M. Shankrayya and K.M. Vishawanath et al., 2010. Antiulcer and anti-inflammatory activity of aerial parts Enicostemma littorale blume. Pharmacology, 2: 369-373.
CrossRef | Direct Link |
Sohail, M.N., F. Rasul, A. Karim, U. Kanwal and I.H. Attitalla, 2011. Plant as a source of natural antiviral agents. Asian J. Anim. Vet. Adv., 6: 1125-1152.
Sthishkumar, R., P.T.V. Lakshmi and A. Annamalai 2009. Effect of drying treatment on the content of antioxidants in Enicostemma littorale blume. Res. J. Med. Plant, 3: 93-101.
CrossRef | Direct Link |