Authored by: Mohammad Ayub - Ibn Sina GIHM Student
The Melilotus also known as the sweet clover is an annual/ biennial herbaceous plant which is found to originate in the Mediterranean and central Asia in their subtropical regions. Nevertheless, the herb has also been pioneered in North America, Africa and Australia. For years the herb has been used in many aspects of life in various forms. The sweet clover has been used in agriculture as green manure for soil improvement and fertility, it has also been used as forage and yields pale honey that gives a mild taste (Jasicka-Misiak et al., 2017). This honey may be used in foods and for medicinal purposes (Arora and Mathur, 2019). The seed meal may also be used as protein supplements in cattle. As well as this, the Melilotus is also a nitrogen-fixing plant, this means that the herb can convert nitrogen in the air to nitrogen compounds which act as fertilizers and aid in the growth of the plant (Nationwide, 2019). Besides this being beneficial for the nitrogen-fixing plant itself but it is also beneficial for neighbouring plants too (Rojas-Sandoval, 2019). This implies that the soil nitrogen in areas invaded by the sweet clover will possess large amounts of nitrogenous compounds such as ammonium and nitrates.
However, the sweet clover consists of varying amounts of an organic chemical compound called Coumarin, this compound is responsible for the scent of the herb and in some animal is shown to have a destructive effect on the liver cells (Upane, 2019). Due to this, dried leaves may be toxic and may also prevent blood clotting. In order to avoid this consequence, a daily intake of 5mg of Coumarin should not be exceeded (fresh Melilotus is safe to use). As well as this, there are other minor side effects of the sweet clover such as occasional stomach aches and some individuals may also experience allergic reactions (Lam, 2019).
In addition to this, the Melilotus is also used in modern medicine to treat many types of diseases such as, varicose veins and chronic venous insufficiency, where the veins in the legs and feet become inflamed and swollen which restricts blood flow back to the heart. The use of the sweet clover thins the blood and aids in the return of the blood to the heart. Lymphatic filariasis, haemorrhoids and digestive disorders are also treated with the use of medicines that include extracts of the sweet clover. Yet, these medicines would need to be used long-term in order for any effect to be realised (Melilotus officinalis Melilot, Sweetclover PFAF Plant Database, 2019). The sweet clover is also used to treat sleeplessness and nerve tension by means of tea infusions (Sweet Clover, 2019). Melilotus can also be manufactured into drops and ointments to treat eye inflammations and rheumatic pains and also help reduce the risk of phlebitis and thrombosis. The fluid extract of the sweet clover may be used in liquid syrups and the dried extracts may be manufactured into tablets and capsules. Having this being said, the sweet clover is most commonly prepared by means of tea infusions (Lam, 2019).
Despite the sweet clover being used for agriculture and modern medicinal purposes, it was and still is used in Greco-Islamic herbal medicines (Saad and Said, 2013). The sweet clover prevents and terminates tumours of the eyes and ears and, if taken with grape juice (when made into rubuub) also helps relieve eye and ear pain. As well as, eye and ear tumours, the sweet clover also eliminates the tumours of the anus and testicles (Heyadri et al., 2015). This herb also aids with the recovery of scratches and wounds which are wet (balghami or damawi) if used as damad with other herbs which is qawbid. The sweet clover also acts as a painkiller and backs up internal organs, in addition to burning qawbid, muhalil and naazij.
Unlike many plants, sweet clover can be cultivated within a wide range of environments, can adapt to various climates and can continue to thrive in different soil conditions especially in calcareous soils. The Melilotus is easily able to grow in many areas, they may be found in grassland, arable fields/land, wasteland and along roadsides (Melilotus (PROSEA) - PlantUse English, 2019). The herb is drought tolerant and is capable of blooming in such conditions. All that is required for growth, is enough moisture for germination after which the plant can readily survive under dry conditions. However, the sweet clover is also able to thrive in well-irrigated places as well. Nevertheless, in order to achieve optimal growth, the sweet clover requires well-drained, adequately moist, fertile soil to grow in, however, in spite of this, growth is not encouraged in shady areas (Yellow Sweet Clover (Invasive Exotic Plants of North Carolina) · iNaturalist.org, 2019). The soil must also maintain a pH of 6.5-7.5, acidic soils do not favour cultivation, yet neutral and basic (alkaline) soils are better suited for the development of the herb, saline soil is also desirable for extensive growth. In addition to this, if the plant is cultivated in either heavy clays, medium loamy and light sands, the crop will successfully mature (Melilotus officinalis Melilot, Sweetclover PFAF Plant Database, 2019).
Arora, R. and Mathur, P. (2019) Melilotus (PROSEA) - PlantUse English. Uses.plantnet-project.org. [Online] [Accessed on 14 June 2019] https://uses.plantnet-project.org/en/Melilotus_(PROSEA).
Heyadri, M., Hashempur, M., Ayati, M., Quintern, D., Nimrouzi, M. and Mosavat, S. (2015) 'The use of Chinese herbal drugs in Islamic medicine'. Journal of Integrative Medicine, 13(6) pp.363-367.
Jasicka-Misiak, I., Makowicz, E. and Stanek, N. (2017) 'Polish Yellow Sweet Clover (Melilotus officinalis L.) Honey, Chromatographic Fingerprints, and Chemical Markers'. Molecules, 22(1) p.138.
Lam (2019) Sweet clover (Yellow sweet clover, yellow melilot, ribbed melilot or common melilot - Melilotus officinalis (L.) Lam) - Medicinal Plants - Kooperation Phytopharmaka. Koop-phyto.org. [Online] [Accessed on 14 June 2019] https://www.koop-phyto.org/en/medicinal-plants/sweet-clover.php.
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Nationwide, S. (2019) Sweet Clovers. Sare.org. [Online] [Accessed on 14 June 2019] https://www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition/Text-Version/Legume-Cover-Crops/Sweet-Clovers.
Rojas-Sandoval, J. (2019) Melilotus officinalis (yellow sweet clover). Cabi.org. [Online] [Accessed on 14 June 2019] https://www.cabi.org/ISC/datasheet/33697.
Saad, B. and Said, O. (2013) Greco-Arab and Islamic herbal medicine. Hoboken, N.J.: Wiley, p.489.
Sweet Clover. (2019) Phytochemicals.info. [Online] [Accessed on 14 June 2019] https://www.phytochemicals.info/plants/sweet-clover.php.
Upane (2019) GISD. Iucngisd.org. [Online] [Accessed on 14 June 2019] http://www.iucngisd.org/gisd/species.php?sc=1170.
Yellow Sweet Clover (Invasive Exotic Plants of North Carolina) · iNaturalist.org. (2019) iNaturalist.org. [Online] [Accessed on 14 June 2019] https://www.inaturalist.org/guide_taxa/355865.
Yellow sweet clover: Topics by WorldWideScience.org. (2019) Worldwidescience.org. [Online] [Accessed on 16 June 2019] https://worldwidescience.org/topicpages/y/yellow+sweet+clover.html.