Observations placeholder

Extracted from The sacred lotus (Nelumbo nucifera)– phytochemical and therapeutic profile - Dr Pulok K. Mukherjee1,2,*, Debajyoti Mukherjee1, Amal K. Maji1, S. Rai1 and Michael Heinrich2  Article first published online: 8 JAN 2010  DOI: 10.1211/jpp.61.04.0001  2009 Royal Pharmaceutical Society of Great Britain

The flowers are solitary, large, 10–25 cm in diameter, white, pink or pinkish white, fragrant and have peduncles arising from the nodes of the rhizome, and 1–2 cm long sheathing at the base. The sepals, petals and stamens are spirally arranged, passing gradually one into another.

Traditional uses

Flowers are traditionally used to treat diarrhoea, cholera, fever, hepatopathy, hyperdipsia and many bleeding disorders. The flower stalks of N. nucifera have been used as one of the ingredients of ‘Madhucasava’, a unique fermenting medium used for microbiological screening. The flowers are used in the treatment of premature ejaculation, abdominal cramps and bloody discharges, and as a cardiac tonic. The flower stalk is used for the treatment of bleeding gastric ulcers, excessive menstruation and post-partum haemorrhage. The lotus honey is used as a tonic and for the treatment of eye infections.

Pharmacology and toxicology

Hypoglycaemic activity

Sun-dried flower powder of N. nucifera, as well as the aqueous and alcoholic extract of the flower, produced significant hypoglycaemia in fasting normal albino rabbits. There was no significant difference in the activities of 1000 mg/kg of the test drug (sun-dried powder of the flower) and equivalent amounts of the extracts; the effect was approximately 50% of that produced by 250 mg/kg tolbutamide.  In normal rabbits, the extract at a dose of 1000 mg/kg significantly lowered hyperglycaemia induced by subcutaneous injection of 0.5 mg/kg adrenaline hydrochloride.  In-vitro studies with rat hemidiaphragm revealed that the sun-dried flower powder significantly enhanced the effect of insulin. The improvement of glucose tolerance may also be due to increased peripheral glucose utilisation caused by increased sensitivity of skeletal muscle to endogenous insulin.

Antioxidant activity

Jung et al. examined the potential of N. nucifera stamens to scavenge DPPH free radicals and peroxynitrites (ONOO−), and the inhibition of total ROS generation by kidney homogenates using 2′,7′-dichlorodihydrofluorescein diacetate. The methanol extract showed strong antioxidant activity in the ONOO− system and marginal activity in the DPPH and total ROS systems. In a similar fashion, seven known flavonoids were isolated from lotus stamens, most of which also showed potent antioxidant activity.  The glycosides nelumboroside A, nelumboroside B, isorhamnetin glycoside and isorhamnetin rutinoside isolated from N. nucifera stamens showed potent antioxidant activity in DPPH and ONOO− assays.   ‘Yunyupju’, a liquor made from the blossoms and leaves of lotus, has been reported to have antioxidant activity, with an IC50 value of 1.07 ± 0.04 mg.

Antipyretic activity

The ethanol extract of stalks of N. nucifera was evaluated for its antipyretic potential on normal body temperature and yeast-induced pyrexia in rats. The stalk extract showed significant activity in both models at oral doses of 200 and 400 mg/kg. In the model of yeast-provoked pyrexia, the extracts showed dose-dependent lowering of body temperature up to 4 h; the results were comparable to those with paracetamol.

Aldose reductase inhibitory activity

Two glycosides, namely kaempferol 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside and isorhamnetin 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside, isolated from the methanol extract of stamens of N. nucifera exhibited a high degree of inhibitory activity against rat lens aldose reductase in vitro, with IC50 values of 5.6 and 9.0 μM, respectively.

Hepatoprotective activity

Oral administration of a 50% hydroalcoholic extract of N. nucifera flowers (200 and 400 mg/kg) showed significant dose-dependent protective effects against carbon-tetrachloride- and paracetamol-induced hepatotoxicity in rats. A 400 mg/kg oral dose of 50% aqueous ethanolic extract of flower exhibited the most significant protective effect. The hepatoprotective mechanisms of flower extract might be due to prevention of lipid peroxidation, inhibition of cytochrome P450 activity, stabilising of the hepatocellular membrane, and enhancement of protein synthesis