Habitat
It grows throughout India, and is often cultivated, up to an altitude of 1,500 m.

Morphology Description (Habit)
M.charantia, is a monoecious climber. The stem is slender, more or less pubescent; the leaves are suborbicular, 5-7 lobed, hairy; the flowers are yellow and solitary; the fruits are pendulous, fusiform, beaked and ribbed with numerous tubercles; the seeds are brownish, compressed and embedded in red pulp.

Principal Constituents
The fruits and leaves of the plant contain two alkaloids, one of them being momordicine. The plant is reported to contain a glucoside, a saponin-like substance, a resin with an unpleasant taste, an aromatic volatile oil and a mucilage. The seeds contain an alkaloid (m.p. 236°) and an anthelmintic principle in the germ; they also contain urease¹.
The fruit contains ascorbigen, a bound form of ascorbic acid released by heating with water in an atmosphere of carbon dioxide or nitrogen. Large sized fruits, borne by certain types of M. charantia, are richer in ascorbigen than small fruits borne by other cultivated types².
The free amino acids present in the fruit are: aspartic acid, serine, glutamic acid, threonine, alanine, g-amino butyric acid and pipecolic acid. The green fruit contains luteolin. Carotene is the principal pigment of carpels, while lycopene characterizes the red aril³.
The fruits and seeds of M.charantia yielded a polypeptide (mp 240°), viz. p-Insulin, which was considered to be similar to bovine insulin⁴.

Pharmacology
Oral administration of fresh fruit juice (dose, 6 c.c./kg. body wt.) lowered the blood sugar level in normal and alloxan-diabetic rabbits. Oral administration of alcoholic extracts of the plant to some diabetic patients did not produce any hypoglycaemic action⁵.
p-Insulin, a polypeptide from the fruits and seeds rapidly decreased and normalized the blood sugar level in rats⁴.

Clinical Studies
p-Insulin was tested in a controlled clinical trial. In juvenile diabetics, the peak hypoglycemic effect was observed after 1-8 hrs; in patients with maturity onset diabetes, maximum fall in blood sugar level was noted after 12 hrs⁴.

Toxicity
The juice appears to be also abortifacient. However, the possibility of separating a non-toxic hypoglycemic factor cannot be ruled out.

Indications
The fruits have long been used in India as a folk remedy for diabetes mellitus. Lectins from bitter gourd have shown significant antilipolytic and lipogenic activities.

1. Quisumbing, 945-46; Rivera, Amer. J. Pharm., 1941, 113, 281; Rehm et. al., J. Sci. Fd Agric., 1957, 8, 679; Rehm & Wessels, ibid., 1957, 8, 687; Airan & Ghatge, Curr. Sci., 1950, 19, 19; Chem. Abstr., 1930, 24, 684; Nath & Ullah, Ann. Biochem., 1956, 16, 89.
2. Bose & Guha, Sci & Cult., 1959-60, 25, 387.
3. Rao et. al., J. sci. industr. Res., 1956, 15C, 39; Ganju & Puri, Indian J. med. Res., 1959, 47, 563; Palmer, 76.
4. Handa, et. al., Fitoterapia, 1989, 60, 208; Chem Abstr, 1992, 117, 84115.
5. Kirt. & Basu, II, 1131; Nadkarni, I, 806; Chem. Abstr., 1945, 39, 2623; Sharma et. al., Indian J. med. Res., 1960, 48, 471; U.S.D., 1955, 1758; Rivera, Amer. J. Pharm., 1942, 114, 72.