Guma-guma is an erect, annual, hairy herb growing to a height of 30 to 90 centimeters. Leaves are linear or elliptic-lanceolate, 5 to 7.5 centimeters long, blunt at the tip, and toothed at the margins. Whorls of many flowers are 1 to 1.5 centimeters in diameter. Calyx is 5 to 7 millimeters long, and obliquely turbinate, with minute teeth, erect or spreading horizontally. Fruits are four-seeded.
- I n open grasslands at low altitudes in Nueva Viscaya and Bataan Provinces in Luzon; and in Panay and Mindanao (Lanao and Davao).
- Also occurs In tropical Asia to Malaya.
- On distillation, yields a small amount of essential oil.
- Decoction of herb boiled with soda solution emits a strong odor; when condensed, the vapor yields ammonia and a volatile alkaloid in the distillate.
- Methanolic extract of aerial parts yielded alkaloids, steroids, tannins flavonoids, and glycosides.
- Study of essential oil from the seed of Leucas zeylanica yielded 56 components. The major components of were oleic acid(12.57%), hexadecanoic acid(10.36%),1-octene-3-ol(7.96%), caryophyllene(5.98%), 2,4,6-trimethyl-1,3,6-heptatriene(5.63%), etc. (see study below) (4)
- Considered a stimulant and antirheumatic.
- Pharmacognostic study of methanolic extract of aerial parts yielded deep green color, characteristic odor and mucilaginous and slightly bitter taste.
- Studies have shown antibacterial, antioxidant, mosquito repellent, antifungal, photoprotective, analgesic, cytotoxic, CNS depressant properties.
Leaves, flowers, roots.
- Herb has a bitter taste; used as flavoring or pot herb.
- In Bali, sometimes used as flavoring.
- Used for coughs, toothaches and abdominal pains.
- In China, used for coughs.
- In China and Malaya, poultice of leaves used for wounds and sores.
- Poultice of leaves also used for itches, headaches and vertigo.
- In Reunion, used as stimulant and antirheumatic.
A decoction of leaves and Nigella seed or the fresh juice of tumeric and rice, used for ulceration.
- Juice of leaves used for headaches and colds.
- In Ceylon, plant used for mild fevers associated with indigestion; also, for pain caused by intestinal worms.
- Leaves used for itches.
- Bitter roots and bitter and pungent leaves used for skin diseases and for scabies.
- Infusion used as insecticide.
- In Malaysia, leaves taken as sedative and for wound healing. Entire plant rubbed on the abdomen after child-birth. Leaves used as anthelmintic.
- In India, used for fever, scorpion and snake bites. Leaves and flowers used for jaundice.
- In Sri Lanka, a principle vermifuge ingredient. Used for anorexia, flatulence, colic; in mixture, used to treat malaria. (11)
- In Thailand, leaves, roots, and flowers are used for weaning: the plant parts are crushed and smeared on the nipple. (10) Poultice of leaves used for wound healing and to stop bleeding. (12)
• Antibacterial / Photoactivity: In a study of 32 plants species collected from serpentine (ultramafic) soils in Sri Lanka and screened for antimicrobial properties, L. zeylanica showed photo-mediated activity against S. aureus and B. subtilis. L. zeylanica showed population-level variation in photoactivity. Study suggests plants from serpentine environments may have altered antimicrobial activities compared to non-serpentine environments, and that attention is needed in deciding on the substrate and habitat when collecting plants to test for antimicrobial properties. (3)
• Essential Oil / Antioxidant / Antibacterial: Study of essential oil showed the major components were: oleic acid, hexadecanoic acid, 1-octenen-3-oil, caryophyllene, etc. The essential oil showed scavenging antioxidant activity. Antibacterial activity showed inhibition of test bacterial growth, especially E coli and Salmonella enteritidis. (4)
• Protection Against Ethanol and H2O2-induced Hepatic Oxidative Stress: Study of Leucas zeylanica showed protection against oxidative stress on hepatic tissue induced by exposure to ethanol and Fenton's reagent. Results were attributed to the presence of antioxidant phytochemicals, including polyphenols and flavonoids. (6)
• Essential Oil / Anthelmintic: Study evaluated the efficacy of L. zeylanica on Enterobius vermicularis infections by use of a whole plant decoction taken twice daily for seven days. Results showed L. zeylanica is a highly effective treatment for E. vermicularis infections in adults. (7)
• Antifungal / Leaves: Study evaluated the antifungal susceptibility of clinically isolated dermatophytes to methanol extracts of L. aspera and L. zeylanica leaves. Results showed remarkable antidermatophytic activity with zones of inhibition ranging from 5 to 10mm, with maximum inhibition on Penicillium sp and minimum inhibition for Candida tropicalis. (13)
• Photoprotective Potential: Study evaluated the aqueous extracts of eleven medicinal plants in Sri Lanka for photoprotective activity by determining the UV filtering potential. Extracts showed high antioxidant activity by DPPH and ABTS assays. Leucas zeylanica was one of six plants that displayed SPF value ≥ 25, which is higher than two commercial photoprotective creams. L. zeylanica and O. mungos exhibited high UV absorbance in 260-350 nm range suggesting potential in being broad spectrum sunscreens. (14)
• Antioxidant / Analgesic / Cytotoxic / CNS Depression: Study of an ethanolic extract of Leucas zeylancia showed dose-dependent CNS depressant activity by hole cross test, analgesic effect by acetic-acid induced writhing and formalin-induced paw licking and biting tests, cytotoxic effect with potent toxicity to Artemia salina (LC50 11.063 µg/ml) in Brine shrimp lethality assay, and concentration-dependent antioxidant effect. by DPPH assay (15)