Melinis minutiflora
[Introduction and Common Names] [Chemical Compounds and Toxicity] [Uses and Efficacy] [References] [Return to medicinal plants list]
Melinis minutiflora Beauv. (listed under the Family Gramineae or Poaceae) also is referred to as Panicum minutiflora and P. melinus. It is a seed propagated tropical grass (C4) that grows to height of approximately 3 ft. It originated in Africa, though it can now be found in much of South and Central America, the Caribbean, and parts of India. M. minutiflora is considered a nuisance weed in many parts of the world including Hawaii, Brazil, Venezuela, and Colombia (Duke, 1983). Hawaii is currently tracking its spread on the islands.
Most of the research with this grass has focused on its nutritional value as a pasture grass. It can be an easy to establish pasture grass. However, it also can outgrow all other grasses and weeds in a pasture and form monotypic stands. Like many tropical grasses, it does not make good hay or silage (although it is used for hay and silage in some tropical countries). M. minutiflora can be overgrazed and damaged from repeated mowings (e.g., for making hay).
James A Duke's Handbook of Energy Crops (1983, unpublished) provides nutrition information, as well as, chemical, medicinal, and ecology information. The University of Hawaii's web site has several pictures available of M. minutiflora.
Common names for Melinis minutiflora include:
- Herbe molasses
- Molasses grass (U.S.)
- Puakatau
- Stinkgrass (U.S.)
- Yeragua (Colombia)
- Yerba agua (Dominican Republic)
- Yerba melao (Puerto Rico)
Little is known about the chemical composition and toxicity of M. minutiflora. Preliminary chemical analyses at Cornell University indicate the presence of phenolics in the roots. The volatile oil (from the glanular hairs) contains fatty acids, esters, and probably phenolics (Duke, 1983). The leaves contain calcium oxalate crystals (Lersten, 1983).
No toxicity studies could be found. Since little is known about the chemical composition (beyond nutritionally important compounds), it is difficult to assess the toxicity of the plant when used for medicinal purposes. Some phenolics are poisonous, while others are known to have antioxidant and anticancer properties.
Oxalates (including calcium oxalates) have caused adverse effects in livestock and can decrease the availability of calcium in a plant. For example, some of the calcium in alfalfa is in the oxalate form and unavailable to ruminants. Ruminants tend to be more tolerant of oxalates then non-ruminants (e.g., horses), because rumen microbes degrade the oxalate. Therefore, if ruminants are slowly exposed to a diet high in oxalates (over an approximately 4 day period), the population of oxalate degrading microbes in the rumen increases sufficiently to prevent oxalate poisoning. Given that M. minutiflora is used as a pasture plant and that most treatments with it are for external parasites, one might assume that the level of oxalates will not cause adverse effects. However, oxalate levels can vary with the growing season, so one should be cautious when using any oral treatments with the grass, especially with non-ruminants (Cheeke, 1998). Studies need to be conducted to determine the types of phenolics and other bioactive compounds in M. minutiflora, in order to better assess its potential toxicity, identify the active compounds, and determine variation in the compounds at different growth stages.
In the Dominican Republic, the roots of M. minutiflora are used for internal parasite infections in animals. The roots are washed, ground, mixed with water, and given as an oral treatment. The anti-parasitic properties of M. minutiflora are currently being studied at Cornell University. Preliminary tests have been conducted with Haemonchus contortus. These tests indicate that crude ethanol extracts of the grass decrease the viability of H. contortus eggs. Further studies on the effect on third stage larvae are underway.
M. minutiflora is insecticidal, arachnicidal, and an insect repellent. In Tanganyika, the leaves are rubbed on livestock to repell insects. Studies conducted by Mwangi, et al. (1995) and Hernandez, et al. (1990), demonstrate that the grass repells ticks (Rhipicephalus appendiculatus and Boophilus microplus). Studies also have shown that M. minutiflora, when inter-cropped with maize, repelled cereal stemborer females from oviposting on the maize (Khan, et al. 1997).
Not all of the references in the list below were used in writing this web page. They are included here so that a more complete resource list is available for those interested in the subject area.
- Calle, Alvarez J., Hernandez, E.L., Riano, I., and Galindo, G. 1986. Isolation and identification of some compounds in oil from a pasture grass Melinis minutiflora. Revista Colombiana de Ciencias Quimico-Farmaceuticas, (15): 83-86. (Spanish).
- Charchar, J.M. and Huang, C.S. 1991. Survival of Pratylenchus brachyurus in root pieces of molasses grass Melinis minutiflora. Brazilian Phytopathology (Fitopatologia Brasileira), 16(1): 22-25. (Portuguese).
- Duke. 1983, unpublished. James A Duke's Handbook of Energy Crops, http://newcrop.hort.purdue.edu/newcrop/duke_energy/Melinis_minutiflora.html
- Hernandez, L., Parra, D., and Ahumada, A. 1990. Repellent and acaricidal activity of the oil and some chromatographic fractions of the grass Melinis minutiflora against Boophilus microplus. Revista Colombiana de Ciencias Quimico-Farmaceuticas, (17): 45-50. (Spanish).
- Juarez, Lagunes, F.I., Fox, D.G., Blake, R.W., and Pell, A.N. 1999. Evaluation of tropical grasses for milk production by dual-purpose cows in tropical Mexico. Journal of Dairy Science, 82(10): 2136-2145.
- Kahn, Z.R., Chiliswa, P., Ampong Nyarko, K. Smart, L.E., Polaszek, A., Wandera, J., and Mulaa, M.A. 1997. Utilisation of wild gramineous plants for management of cereal stemborers in Africa. Insect Science and its Application, 17(1): 143-150.
- Lersten, N.R. 1983. Crystals of calcium compounds in Gramineae. New Phytol, 93(4): 633-638.
- Mwangi, Esther, N., Essuman, S., Kaaya, G.P., Nyandat, E., Munyinyi, D., and Kimondo, M.G. 1995. Repellence of the tick Rhipicephalus appendiculatus by the grass Melinis minutiflora. Tropical Animal Health and Production, 27(4): 211-216.
- University of Hawaii. http://www.botany.hawaii.edu/faculty/cw_smith/mel_min.htm
- Watson, L. and Dallwitz, M.J. Undated web site. http://www.keil.ukans.edu/delta/grass/www/melinis.htm