By Maryann Readal
The Herb Society of America’s Herb of the Month for August is the makrut lime, Citrus hystrix, a member of the Rutaceae family. This lime is also known as kaffir lime or Thai lime, and also wild lime. You may have spotted it in a produce market or Asian supermarket and wondered what makes it different from an ordinary lime. It certainly looks different, in that it has a gnarly, bumpy skin. The very aromatic leaves are different, too, because they look as though they are two leaves attached to each other. The juice is sour and bitter, and so is not usually used in cooking because it can overwhelm other flavors.
This lime has been widely grown in Asia for so long that it has become naturalized in many countries. Therefore, no one is certain of its origin. It is a staple ingredient in Thai, Cambodian, Vietnamese, and other Southeast Asian cuisines. The leaves, which are sold frozen, fresh, or dried, are usually finely chopped and incorporated into food or sprinkled on top. The makrut lime can be planted outdoors in warmer climates, or grown in a pot that can be brought inside for the winter in colder climates. It is a host plant for the giant swallowtail butterfly.
Recently, there has been a concerted effort among chefs and other food professionals to replace the name kaffir lime with the name makrut lime or Thai lime. The word “kaffir” has a derogatory, racist connotation in South Africa, and it has a derogatory religious meaning in Middle Eastern countries.
Like other citrus species, the leaves, seeds, skin, bark, and root of the makrut lime have a number of medicinal benefits. In Southeast Asian countries, it has been used in shampoos, ointments, and in toothpaste and mouthwash products. A recent study published in the journal Nutrition by Kooltheat et al. (2016) has shown that the essence of the lime used on the teeth and gums can prevent tooth decay. In Malaysian countries, the leaf is rubbed into the gums and on the teeth as a mouth and dental cleaner. And because of the fruit’s limonene and citronella content, it is added to shampoos to treat lice. The lime has been used in Ayurvedic medicine to treat colds and congestion and to help with digestion. Its oil is also used in aromatherapy to reduce stress, anxiety, and fatigue. In Thailand, makrut lime is added to household cleaning products. The authors of an article in Drug Intervention Today conclude that because of the lime’s antioxidant, anti-inflammatory, and antimicrobial components, “extensive investigation on its pharmacology and clinical trials is needed to exploit their therapeutic utility to cure various diseases” (Abirami et al., 2014).
Distillers and bartenders have discovered that the addition of makrut lime to their beverages can make distinctive-tasting and aromatic drinks. Treaty Oak Distilling in Dripping Springs, Texas, has developed a gin that incorporates the makrut lime, as well as other herbs. They describe their gin as making you “rethink everything you thought you knew about this spirit.”
Research on the medicinal qualities of the makrut lime underscores the importance of protecting native species that have been used for centuries as medicinal plants. It is promising that there is ongoing research on the effective medical applications of not only the makrut lime, but many other native medicinal plants as well.
For more information on the makrut lime, please visit The Herb Society of America’s website, where you will find more information, recipes and a beautiful screen saver of this unusual-looking fruit. https://www.herbsociety.org/hsa-learn/herb-of-the-month.html
Kooltheat, N. et al. Kaffir lime leaves extract inhibits biofilm formation by Streptococcus mutans. Nutrition. 32, (4). April 2016. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0899900715004165?via%3Dihub#!
Abirami, A., Nagarani, G., & Siddhuraju, P. The medicinal and nutritional role of underutilized citrus fruit-Citrus hystrix (Kaffir Lime): A Review. Drug Intervention Today. 6(1), January, 2014. Retrieved from http://docplayer.net/38584426-The-medicinal-and-nutritional-role-of-underutilized-citrus-fruit-citrus-hystrix-kaffir-lime-a-review.html
Photo Credits (from top): Makrut lime fruits (Creative Commons); Makrut lime leaves (Wikimedia Commons, courtesy Forrest & Kim Starr), Waterloo Old Yaupon Gin (courtesy Treaty Oaks Distillery).
Medicinal Disclaimer: It is the policy of The Herb Society of America, Inc. not to advise or recommend herbs for medicinal or health use. This information is intended for educational purposes only and should not be considered as a recommendation or an endorsement of any particular medical or health treatment. Please consult a health care provider before pursuing any herbal treatments.
Maryann is the Secretary of The Herb Society of America. She is a Master Gardener and a member of the Texas Thyme Unit in Huntsville, TX. She gardens among the pines in the Piney Woods of East Texas.