Gen info
- The genus name is Greek-derived, mythology dedicating the water lily to the semi-divine maidens, the nymphs. The genus has roughly about 40 species found in the tropical and temperate climates of both hemispheres. There is confusing synonymy as plants are placed in different species or species sometimes misapplied. There are many variants and hundred of hybrids.
- Nymphaea nouchali is the national flower of Sri Lanka where it is called Nil Manel.

Botany
Lauas is long-lived aquatic herb, with rootstock rooting in the mud. Leaves are long-stalked and leathery, floating on the surface of water, ovate to almost circular, prominently toothed, slightly peltate, 12 to 15 centimeters across, with the base deeply heart-shaped, and densely hairy beneath. Petioles are long, slender and submerged. Flowers are fragrant, white or red, about 8 centimeters in diameter, borne on long peduncles. Petals are linear-oblong to lanceolate. Fruits are globular, with longitudinally numerous, striated seeds.

Distribution
- In shallow lakes and ponds, often locally abundant, from northern Luzon to Mindanao.
- Usually cultivated for its attractive flowers.
- Also occurs in tropical Asia to Malaya.

Constituents
- The leaves and rhizomes contain an abundant amount of tannic acid, an alkaloid resembling nupharin, glucose, metaarabic acid, starch, fat; and ash.
- The leaves contain myricitin, saccharose and phytosterin.

Properties
- The juice is bitter and astringent has some narcotic properties.
- Flowers are astringent and cardiotonic.
- Juice is bitter.

Parts utilized
Rhizomes, flowers, seeds

Uses
Nutrition
- The seeds, long stalks of flowers and rhizomes are edible; eaten boiled or roasted.
- Roots and rhizomes often eaten raw.
- The tender leaves and flower peduncles of the red and blue-water lily are also valued as food.
- Flowers stalks considered an excellent source of iron and a fair source of calcium.
Folkloric
- Juice is astringent; decoction of the juice used as injection for gonorrhea.
- Plant juice considered mildly narcotic, rubbed on the forehead and temples to induce sleep.
- Powdered roots used as demulcent for piles; also for dysentery and dyspepsia.
- Powdered root prescribed for piles as demulcent; also for dysentery and dyspepsia.
- Flowers used as astringent and cardiotonic.
- In Bangladesh, the roots used by the traditional healers of the Tripura, Marma and Murong tribes to treat dysuria, urinary tract infections and leucorrhea. Also, used for indigestion, heart diseases, stomachaches, cancer, and as anti-hemorrhagic.
- In Nepal and India flowers used in treatment of diabetes.
- In Ayurveda and Siddha systems of medicines, used for diabetes, liver disorders, urinary problems, menorrhagia, blenorrhagia; also used as tonic and aphrodisiac.

Studies
• Antioxidant: Study showed high levels of non-enzymatic antioxidants like phenols, flavonoids, tannins, etc., as well as antioxidant potential in the methanol extracts of dry flowers. High levels of enzymatic antioxidants were found in the fresh flower aqueous extracts. (3)
• Antidiabetic / Flowers: Flower extract showed significant reduction of blood glucose in diabetic rats.
• Antidiabetic / ß-Cell Stimulation: Hydroalcoholic extract also showed a dose-dependent response possibly through ß-cell stimulation, release of insulin and activation of insulin receptors.
• Antihepatotoxic : Study of alcoholic extract of N. stellata flowers showed hepatoprotective activity against CCl4-induced hepatic damage possibly through cell membrane stabilization, hepatic cell regeneration and antioxidative enzyme activation. (6)
• Cholinergic : Study of alcohol extract of defatted fruits of N. stellata produced mild sedation and ataxia, potentiated hexobarbitone-induced hypnosis in mice. Large doses after atropinization caused a rise in blood pressure and a stimulant effect on guinea pig ileum, suggesting an unstable cholinergic principle.
• Antimicrobial : Flower extract showed activity against P. aeruginosa, B. cereus, S. aureus.
• Analgesic . Anti-Inflammatory: Study showed significant analgesic and antipyretic activity. The anti-inflammatory activity was comparable to hydrocortisone.
• Intestinal Alpha-Glucosidase Inhibitory Activity / Toxicological Evaluation: Study showed potent rat intestinal alpha-glucosidase inhibitory activity for maltose hydrolysis. Genotoxicity assessment showed the extract did not cause genotoxic in Ames test. (5)
• Antihyperglycemic / Antihypolipidemic: Study of N. stellata flower extract exhibited blood sugar lowering effect as well as an antihyperlipidemic effect on alloxan-induced diabetic rats. (7)
• Nymphayol / Antidiabetic: Chloroform extract showed significant glucose lowering effect. Study isolated a nymphayol, found to lower blood glucose, increase insulin content, and a significant increase in beta cell mass. (8)
• Antioxidant / Analgesic / Anti-Inflammatory: A methanolic extract of flowers was evaluated for antioxidant, analgesic and anti-inflammatory activities. The extract exhibited a dose-dependent increase in pain threshold in hot plate method, significant reduced writhing cause by acetic acid and number of licks caused by formalin. There was also significant dose-dependent inhibition of carrageenan-induced paw edema. There was good antioxidant potential exhibited in DPPD, ONOO and total ROS scavenging methods. (10)
• Antimicrobial: Hexane, ethyl acetate and methanolic extracts were evaluated for antimicrobial activity against S. aureus, Pseudomonas aeruginosa, B. subtilis, E. coli, enterococcus faecalis, X. campestris, Streptococcus mutans, Lactobacillus casei, L. acidophilus, Candida albicans. The ethyl acetate extract of leaf were active against all investigated bacteria. (11)
• Lectin / Antibacterial / Antiproliferative: A lectin (termed NNTL) was purified from the extracts of Nymphaea nouchali tuber. NNTL showed toxicity against brine shrimp nauplii with an LC50 of 120±29 µg/ml and exerted strong agglutination activity against four pathogenic bacteria. In addition, it showed antiproliferative activity against EAC (Ehrlich ascites carcinoma) cells. (12)
• Antidiabetic / Antioxidant / Hypolipidemic: Study evaluated the possible antidiabetic, hypolipidemic, and antioxidant effects of an ethanol extract of N. pubescens tuber. Results showed significant reduction of blood glucose, lipids except HDL-C, serum enzymes, significant increase in HDL. The effects may be due to its potent antioxidant potential. (13)

Availability
Wildcrafted.
Cultivated.

Additional Sources and Suggested Readings
(1)
Nymphaea nouchali Burm. f. var. caerulea (Sav.) Verdc. / Cherise Viljoen and Alice Notten / Kirstenbosch National Botanical Garden / January 2002
(2)
Traditional Use of Medicinal Plants in Bangladesh to Treat Urinary Tract Infections and Sexually Transmitted Diseases / Shahadat Hossan, Abu Hanif et al / www.ethnobotanyjournal.org/vol8/i1547-3465-08-061.pdf
(3)
EVALUATION OF ANTIOXIDANT POTENTIAL AND QUALITATIVE ANALYSIS OF MAJOR
POLYPHENOLS BY RPHPLC IN NYMPHAEA NOUCHALI BRUM FLOWERS / V. Nagavani and T Raghava Rao / International Journal of Pharmacy and Pharmaceutical Sciences, ISSN- 0975-1491 Vol 2, Suppl 4, 2010
(4)
A comprehensive review on Nymphaea stellata: A traditionally used bitter / M K Mohan Maruga Raja, Neeraj Kumar Sethiya, S H Mishra / Journ of Advanced Pharma Technology & Research, 2010, Vol 1, No 3, Pp 311-319.
(5)
Intestinal alpha-glucosidase inhibitory activity and toxicological evaluation of Nymphaea stellata flowers extract / Huang Y N, Zhao Y L, Gao X L et al / J Ethnopharmacol. 2010 Sep 15;131(2):306-12. Epub 2010 Jun 30.
(6)
Antihepatotoxic effect of Nymphaea stellata willd., against carbon tetrachloride-induced hepatic damage in albino rats / Bhandarkar MR, Khan A / J Ethnopharmacol. 2004 Mar;91(1):61-4.
(7)
Antihyperglycaemic and antihyperlipidaemic effects of Nymphaea stellata in alloxan-induced diabetic rats / Singapore Med J. 2008 Feb;49(2):137-41. PMID: 18301841
(8)
Partial regeneration of beta-cells in the islets of Langerhans by Nymphayol a sterol isolated from Nymphaea stellata (Willd.) flowers / Bioorg Med Chem. 2009 Apr 1;17(7):2864-70. Epub 2009 Feb 20. PMID: 19272781
(9)
Nymphaea stellata Willd. (accepted name) / Chinese names / Catalogue of Life, China
(10)
Antioxidant, Analgesic and Anti-Inflammatory Activities of Nymphaea Nouchali Flowers / Ishrat Jahan, M. Abdullah A. Mamun, M. Atowar Hossen, J.A.M. Samir Sakir, M. Shamimuzzaman, M. Jashim Uddin and M. Ekramul Haque / Research Journal of Pharmacology, 6: 62-70. / DOI: 10.3923/rjpharm.2012.62.70
(11)
ANTIMICROBIAL AND PHYTOCHEMICAL ANALYSIS OF NYMPHAEA NAUCHALI LEAF EXTRACTS / K.Ammani et al, IJRRPAS, 2(2).142-151.
(12)
Purification and characterization of a Ca(2+)-dependent novel lectin from Nymphaea nouchali tuber with antiproliferative activities. / Syed Rashel Kabir, Md Abu Zubair, Md Nurujjaman, Md Azizul Haque, Imtiaj Hasan, Md Farhadul Islam, Md Tanvir Hossain, Md Anowar Hossain, Md / Bioscience Reports (impact factor: 2.38). 02/2011; 31(6):465-75. / DOI:10.1042/BSR20100126
(13)
Potential antidiabetic, hypolipidaemic and antioxidant effects of Nymphaea pubescens extract in alloxan induced diabetic rats / Shajeela .P .S, Kalpanadevi .V and Mohan .V .R / Journal of Applied Pharmaceutical Science 02 (02); 2012: 83-88