- The best known species of genus Azadirachta (family Meliaceae) is A. indica or Indian neem tree. Two other congeneric species in Southeast Asia are A. siamensis or Thai neem tree, and A. excelsa or Philippine neem tree. (13)
The genus name Azadirachta derives from the Persian word "azad dhirakat" meaning "excellent tree", referring to the economic importance of the plants in the genus. Species epithet "excelsa" is from Latin, meaning "tall." (25)
Marrango is a large evergreen tree that can attain a height of 50 m. Trunk is usually clear up to 20 m tall, with a girth size up to 12.5 m wide. Bark is smooth when young, and fissured in older trees. Leaves are green, alternate, 30-60 cm long, each leaf with about 7-11 pairs of lanceolate to elliptic leaflets, 12.5 cm long and 3.5 cm wide. Flowers are fragrant, greenish white, borne on axillary panicles. Inflorescences are up to 70 cm long, each flower measuring 0.5-o.65 cm long and 0.15-0.25 cm wide, 5-petaled. Fruit is an oblong drupe, 2.1-3.2 cm long, green when young, ripening to yellow, containing one seed. (25)
- Native to the Philippines, Malaysia, Borneo, Indonesia, Vietnam, Papua New Guinea.
- Exotic in Singapore and Thailand.
- Usually in old clearings or secondary forests; sea level to 350 meters altitude.
- Ornamental cultivation.
Endangered in some parts of Southeast Asia.
- Phytochemical screening of ethanolic leaf extract yielded flavonoids, condensed tannin, terpenes, and steroids. GC-MS analysis yielded the presence of seven major compounds. Major component was 9,12,15-octadecatrenoic acid (42.34%), followed by pentadecanoic acid, 14-methyl-,methyl ester (28.99%), phytol (10.63%), 9,12,15-octadecatrueb-1-ol (5.37%), octadecanoic acid, methyl ester (4.36%), 8,12-octadecadienoic acid, methyl ester (4.24%), and hexadecanoic acid, methyl ester (4.06%). (2)
- Activity-directed fractionation of a stem extract isolated four meliacin-type limonoids: two were novel constituents, 2,3-dihydronimbolide (1) and 3-deoxymethylnimbidate (2), with known compounds, nimbolide (3) and 28-deoxonimbolide (4). (see study below) (3)
- Seed oil has fatty acid composition of caprylic acid 0.30%, n-capric acid 0.96%, palmitic acid 9.8%, stearic acid 4.7%, heneicosanoic acid 0.72%, behenic acid 2.76%, and tricosanoic acid 0.75%. (26)
- Studies have suggest antiplasmodial, anticancer, cytotoxic, antioxidant, memory and learning enhancing, antidiabetic, larvicidal, antifertility, insecticidal, anti-termite, nephroprotective properties.
Seeds, leaves, flowers
- Young shoots are eaten as vegetable, although rather bitter. (6)
- In Peninsular Malaysia, young shoots, leaves, and flowers consumed as vegetable. (25)
- Fruit is edible, but not very palatable. (6)
- Malays used the plant to lower blood glucose.
- Used for treatment of diarrhea and dysentery.
- Young shoots and flowers used for stomach and nasal problems.
- Seed oil used in traditional medicine for treatment of diabetes, antibacterial, wound healing and as antifertility medicine,
- Timber: Wood is moderately hard and moderately heavy, with a reddish-brown heartwood which darkens on exposure. Used for making furniture, containers, flooring, light construction, wall paneling, veneers, fiberboard, and a variety of wood-ware like toys, handles. wood carvings, etc.
- Oil: Oil from seeds used for making soap.
- Tannin / Dyestuff: Bark yields tannins.
- Apiculture: Fragrant flowers are source of pollen and nectar.
- Insecticidal: Plant parts are insecticidal. Active principle, marrangin, has effects on insect development. (26)
• Limonoids Cytotoxic against Cancer Cell Lines / Stem: Activity-directed fractionation of a stem extract isolated four meliacin-type limonoids. Nimbolide and 28-deoxonimbolide were broadly cytotoxic against a panel of human cancer cell lines. (see constituents above) (3)
• Osteoprotective / Leaves: Insulin signaling in bone favors whole-body glucose homeostasis by activating ostocalcin, which is important for bone remodeling. The diabetic deficient production of insulin can affect osteocalcin and bone turnover marker. Study evaluated the potential of A. excelsa to improve insulin and osteocacin secretion, resulting in improved bone histomorphometric and bone-turnover marker in STZ-induced diabetic rats. Results showed A. excelsa could attenuate the STZ-induced bone bone loss and reverse the deterioration of bone microarchitecture in diabetic rats. (4)
• Larvicidal / Aedes aegypti / Fixed Oil and Crude Extract from Seed Kernel: Study evaluated activity of various concentrations of fixed oil and crude extract from A, excelsa seed kernel against Aedes aegypti test population. The LC50 of the fixed oil and crude extract were 403.6 and 518.7 ppm, respectively. 100% mortality was achieved in 24 hours at 2000 and 4000 ppm for oil and extract, respectively. The oil was more toxic to Ae. aegypti larvae. There was also molting inhibition. of Ae. aegypti larvae. Histological study suggested damages on the epithelial cells of the midgut, along with hypertrophy and degeneration of the epithelial cells. (5)
• Effects on Memory and Learning Impairment / Amylin and Insulin / Leaves: . Study evaluated the effect of A. excelsa and quercetin consumption on the brain amylin and insulin concentrations as well as memory and learning abilities of STZ-induced diabetic male Sprague-Dawley rats. Treatment with A. excelsa significantly (p<0.05) improved the concentration of both brain amylin and insulin. In the Morris Water Maze test to evaluate learning and memory consolidation, A. excelsa extract and quercetin significantly (p<0.05) attenuated the learning and memory impairments in the STZ-induced diabetic rats, (7)
• Antidiabetic / Leaves: . Study evaluated the antidiabetic properties of an ethanolic extract of A. excelsa in Sprague-Dawley rats. Results showed significantly reduced blood glucose and concentration of HbA1c in diabetic rats by 72.89% and 6,58%, respectively. Plasma insulin level was significantly increased. (8)
• Female Reproductive and Fertility Effects / Leaves: . Study evaluated the effect of ethanol leaf extract of A. excelsa oral dose of 250 mg/kbw every other day for 28 days. Results showed histological changes in the ovaries indicating an increase in the number of secondary follicles, absence of mature follicles, presence of atretic follicles, bleeding tissue and blood vessel congestion. There was a significant increase in progesterone and estrogen levels, decrease in mean of newborn, which proved reduction of fertility of treated females. Study suggests potential for application in rodent control programs. (9)
• Antioxidant / Attenuation of Pancreatic Oxidative Damage: . Study evaluated the antioxidant activity of ethanolic extract of A. excelsa on STZ-induced diabetic rats. Results showed higher potential to increase pancreatic antioxidant enzymes. There was improvement of pancreatic cells replenishment through increase in pancreas weight, Results suggest attenuation of pancreatic oxidative damage and potential for DM treatment. (10)
• Male Reproductive and Fertility Effects / Leaves: . Study evaluated the effect of aqueous and alcohol leaf extract on the testis and fertility of male albino mice, Mus musculus. Histological exam showed affected seminiferous tubules indicating mixing of germ cell types in stages of spermatogenesis, atrophy of spermatogenic elements, increase in the number of spermatozoa in the lumen of seminiferous tubules. Fertility index was reduced. (11)
• Attenuation of Pancreatic Histology in T2 Diabetic Rats: Study evaluated the protective effect of A. excelsa on pancreas and possible toxicity in high-fat diet-fed diabetic rats. Results showed antidiabetic activity via improvement of the structure of pancreatic islets of Langerhans and amelioration of hematology and biochemical parameters. (12)
• Insecticidal / Growth Regulating Properties / Seed Kernel: Bioassays of leaf, bark, and seed extracts of Z. indica and A. excelsa against insects showed greater bioactivity for A. excelsa, which contains azadirachtin as well as marrangin, a new compound related to azadirachtin, in the seed kernels. Marrangin was more toxic than azadirachtin to the Mexican bean beetle, Epilachna varivestis. A. excelsa can be a valuable source of growth-regulating pesticides in the greater rainfall areas of the tropics. (13)
• Insecticidal / Effect on Culex pipiens molestus Larvae / Leaves: Study evaluated the effects of extracts of eight plant species on the second instar of larval stage of Culex pipiens molestus. Three of eight, Azadirachta excelsa, Cleome glaucecens and Quercus infectoria caused 100% mortality of larvae at concentration of 200 µg/ml after 3 days of treatment. LC50 values were less than 150 µg/ml (62.5-140 µg/ml). A. excelsa leaves extract showed larval and pupal mortality oat low concentrations of 40-10 µg/mL, also affecting a delay in larval development. (14)
• Effect on Blood Pressure and Oxidative Stress: Study evaluated the antihypertensive effects of A. excelsa in rats by measuring blood pressure, AST, ALT, LDH, CPK, MDA, SOD, CAT, and GPx along with histopathological changes in the liver, kidney and heart. Results showed alleviation of systolic and diastolic pressures in all treatment groups (p<0.01). Treatment with A. excelsa and quercetin lowered the MDA level in all organs (p<0.05), improved hepatocyte structure, and ameliorated glomerular and renal tubular lesions of the kidney. Study suggests A. excelsa ethanolic leaf extract could attenuate hypertension via amelioration of oxidative stress and improved tissue structure in spontaneously hypertensive rats. (15)
• Effect of A. excelsa and Quercetin on Endocrine Pancreas / Insulin Secretion: Study evaluated the effect of A. excelsa on histology and insulin secretion changes in pancrease of diabetic rats induced with STZ in male Sprague-Dawley rats. Both excelsa and quercetin improved insulin level and promoted ß-cells replenishment. Results suggest a potential for A. excelsa to ameliorate pancreas better than metformin. Both A. excelsa and quercetin have the potential to attenuate pancreatic oxidative damage. Results suggest therapeutic potential for treating DM. (16)
• Antiplasmodial / Leaves: Study evaluated which of the semi-polar extracts of A. excelsa possess the greatest antiplasmodial property against in vitro cultures of blood-stage Plasmodium falcifarum NF54 strain by measuring the level of parasitemia. Results showed A. excelsa had significant effect at higher concentrations against in vitro culture systems of Plasmodium falcifarum parasites. Mechanism of antiplasmodial activity is through killing of malarial parasites. Fraction 3 showed the best antiplasmodial activity, which was attributed to phytochemicals present i.e., flavonoids steroids, phenols, tannins, cardenolides, coumarin, anthraquinones, anthrones, indole, higher alcohols and sugars. (17)
• Improvement of Renal Function and Morphology in STZ-Diabetic Rats / Leaves: Long-term diabetes is associated with serious complications, one of which is nephropathy. Study evaluated the effect of A. excelsa extract in delaying the progression of diabetic nephropathy in Sprague-Dawley rats by measures of fasting blood glucose, kidney oxidative stress, structure and function. Results showed significant reduction (p<0.05) of MDA level and increase (p<.05) of GPx level in both quercetin and extract treated groups. There was also improvement in kidney function parameters and morphological changes of diabetic rats. Results suggest renal therapeutic effects of A. excelsa and quercetin. (18)
• Anti-Termite / Leaves: Study evaluated leaves extracts of A. excelsa against subterranean termite, Coptotermes curvignathus Holmgren. Soils treated with extracts posed a hindrance to the tunneling activities of termites. However, the termites became insensitive to the extracts after a longer period of exposure. Wood mass loss varied significantly with concentration of extracts in the wood blocks. Survival and wood consumption were reduced with exposure to high concentrations of the extract. Results showed inhibitory effect on subterranean termites, C. curvignathus. (19)
• Effect on Enteric Pathogens / Leaves: Study evaluated the inhibitory effects of ethanolic leaf extracts of A. excelsa against some enteric pathogens. Disc diffusion assay showed weak inhibitory effect on Shigella sonnei. However, there was no observed effect against E. coli and Salmonella typhimurium. Results suggest the ethanolic leaf extract may not be effective against enteric pathogens. (20)
• A. excelsa Vinegar Against Plutella xylostella: The diamondback moth, Plutella xylostella is a major pest for crucifers in Malaysia. Study evaluated vinegar derived from A. excelsa against third-instar larvae of P. xylostella to control the pest in a laboratory setting. The A. excelsa vinegar significantly reduced P. xylostella leaf consumption and adult size. Mortality rate of larval, pupae, and adult was significantly increased by application of A. excelsa vinegar. Results suggest potential for use against P. xylostella. (21)
• Repairing and Repopulation of Uterine Structure / Leaves: Reduction of uterine strength is a concern in diabetic women. Study evaluated the mechanism of A. excelsa for repairing the uterus structure in diabetic Sprague-Dawley rats. Administration of plant extract significantly reduced the HbA1c percentage in diabetic rats by 6,58%. Plasma insulin was significantly increased. A. excelsa was able to reduce atrophy and increase the proliferation of stromal cells in diabetic rats. Results suggest A. excelsa has potential as an alternative agent to normalize distribution of stromal cells, and to improve fertility in infertile diabetic women. (23)
• Azadirachtins / Marrangin: Azadirachtin is a highly interesting compound, which took 28 years for its chemical structure to be solve, and another 22 years for its synthesis. It is a valuable natural pesticide, with very low toxicity for vertebrates. (22) Azadirachtins are known as phagorepellent natural products from the seeds of the neem tree Azadirachta indica, which impedes the development of larval insects and sterilize adults. Marrangin (=Azadirachtin L) was discovered in Goeßen and chemically identified by Kalinowski and colleagues. It occurs in the seeds of the marrango tree, A. excelsa (Jack) Jacobs. In sp,e insect species but also in mites like Tetranychus urticae, the biologic activity is significantly superior to azadirachtin A. The value of these biorational compounds, their low vertebrate toxicity, and low toxicity, is globally recognized. Azadirachtin and analogues have gained acceptance in veterinary and human medicine. (24)