Mint, classified under the genus Mentha, represents a captivating group of fragrant herbs within the Lamiaceae family. This diverse genus globally comprises more than 30 species, originating from Eurasia, North America, southern Africa, and Australia. With a history dating back centuries, mint has been naturalized in numerous regions and is an integral part of various cultures worldwide. The distribution of these species is mainly in temperate and tropical/subtropical regions. Due to their ability to freely crossbreed, determining the exact number of taxonomically valid species is challenging, resulting in many intermediary forms. Mints within the Mentha genus are characterized as aromatic herbs, often perennials with leafy runners, stolons, or underground rootstocks.
Japanese mint (Menthol mint) (Mentha arvensis), Peppermint (Mentha × piperita), Spearmint (Mentha spicata), and Bergamot Mint (Mentha citrata) are the major Mentha species that are commercially cultivated.
Economic importance of mint
Mint is used in the manufacture of mint oil and menthol. India is the largest exporter of mint oils. The USA, China, and Germany are the major importers of mint oils from India. Mint oil is obtained mainly from the “Mentha arvensis” herb.
As per the ITC trade map, the world market size of mint oils including peppermint oil stood at 405.7 million USD and India’s share in the world market stood at 216.1 million USD in 2022. India is also the largest exporter of menthol with an export value of 216.6 million USD in the year 2022 of which more than 50% was exported to China, 8.7% to the USA, and 5.1% to Singapore. The global market size of menthol in 2022 was 636.8 million USD.
Japanese mint, also known as menthol mint, plays a crucial role in India’s mint cultivation, contributing approximately 75% to the global menthol mint production.1 Japanese mint is extensively grown in northern India and is a primary source of menthol. Mint oil from Japanese Mint (Mentha arvensis var piperascense) contains high (75–80%) menthol content. It’s essential oil also contains carvone, linalool, and linalyl acetate, making it useful for pharmaceutical preparations and the flavor industry. Japanese mint is propagated mainly through stolons and does not produce seeds. India, China, and Brazil are major producers of Japanese mint. The oil has a bitter cooling taste and harsh odor and is the principal source of menthol. It is used in combating colds, used as an ingredient in cough drops and related pharmaceuticals, dentifrices, cosmetics, mouthwashes, scenting of tobacco products, and flavoring of beverages. Synthetic menthol has entered the market, but its production volumes remain low due to the high cost of manufacturing. Moreover, natural menthol is preferred in the food and flavor industry.1
Mint cultivation
Mint species typically thrive in loam to sandy loam soil rich in humus, with a pH ranging from 6 to 7.5 and good drainage. However, the climatic requirements of mint vary by species. For example, M. arvensis flourishes in tropical and sub-tropical climates, while M. × piperita prefers temperate regions. Generally, temperatures between 20 and 26°C support optimal vegetative growth in most Mentha species. The ideal nitrogen fertilization rates range from 80 to 160 kg·N·ha−1, depending on the species. Adequate irrigation is crucial for Mentha cultivation requiring significant water supply and frequent watering. The specific water needs vary based on climate, species, and soil conditions, potentially reaching up to 1000 mm per season. Most species are susceptible to water stress during summer and waterlogging in winter, depending on the prevailing climate.2
FMCG and pharmaceutical applications of mint
In the FMCG segment, mint is used in the manufacture of cosmetics (toothpaste, mouthwash, shaving creams, shampoos, perfumes, laundry products, soaps, body sprays, etc.), chewing gums, household cleaning products, etc. In the pharma segment, menthol crystals are used in decongestants, lip balms, topical analgesics, skin care products, dental floss, massage oils, and cough medicines. As menthol crystals are cool, refreshing, and have a strong smell, it is used in products that need a strong flavor and are used for their ability to relieve pain and soothe the body.
Traditional uses of mint
Mint herbs have been used since ancient times for various purposes such as in the management of vomiting, reduction of gas in the stomach, facilitation of digestion, management of cough, oral hygiene, heart health, skin health, and pain relief.3 Mint has been suggested in traditional Persian medicine for the treatment of oligomenorrhea and amenorrhea.4 Peppermint and spearmint fragrances were used in embalming and perfumes historically. Mints have also been used as insect repellents.3
Clinical studies of mint
Irritable bowel syndrome
An analysis of 10 human clinical studies revealed that peppermint oil was more effective in managing irritable bowel syndrome symptoms including abdominal pain than a placebo. Although more adverse effects were reported with peppermint oil use compared to placebo, most were mild.5 In another analysis of 12 human clinical studies, peppermint oil was found to be an effective and safe treatment for managing pain and irritable bowel syndrome symptoms.6 Earlier analysis of nine human clinical studies on peppermint oil also reported similar conclusions.7
Energy and endurance
The time to exhaustion in recreational runners was enhanced after intake of 500 ml of drinking water containing 0.05 ml of peppermint oil in a randomized, double-blind, cross-over, placebo-controlled clinical study involving 14 male recreational runners.8
Cognitive performance
In a randomized, double-blind, placebo-controlled clinical study involving 24 healthy adults, peppermint oil improved performance in demanding cognitive tasks and reduced mental fatigue associated with extended cognitive task performance. The treatment involved the oral intake of a capsule containing 0.1 ml of peppermint oil along with 200 ml of full-fat milk before the cognitive and mental fatigue assessments.9
A proprietary aqueous extract of Mentha spicata containing a minimum of 14.5% rosmarinic acid and 24% total polyphenols was found to improve working memory in elderly subjects (50 to 70 years) with age-associated memory impairment (AAMI) in a randomized, double-blind, placebo-controlled study. The extract was also found to improve the ability to fall asleep, vigor-activity, total mood disturbance, and alertness and behavior following wakefulness.10
Hirsutism
Herbal tea prepared using Mentha spicata reduced free testosterone and increased luteinizing hormone, follicle-stimulating hormone, and estradiol in female patients with hirsutism. The herbal tea was taken twice a day for 5 days during the follicular phase of their menstrual cycle. Thus, spearmint tea was considered a possible alternative to antiandrogenic treatment in the management of mild hirsutism.11
In another randomized controlled trial involving female patients with hirsutism, consumption of spearmint tea twice a day for 30 days resulted in a significant reduction in the levels of free and total testosterone along a significant increase in the levels of luteinizing hormone and follicle stimulating hormone. However, the changes in the hormone levels have not resulted in the reduction of hirsutism.12
Knee osteoarthritis
Consumption of spearmint tea (equivalent to 260-300 mg of rosmarinic acid) twice a day for 16 weeks significantly reduced pain, stiffness, and physical disability in adults with knee osteoarthritis in a randomized, double-blind, placebo-controlled study.13
Food uses
Mint leaves, either fresh or dried, are used for their warm, fresh, aromatic, sweet flavor with a cool aftertaste. Mints are used in beverages, jellies, syrups, candies, ice creams, teas, yogurts, and particularly in Arab cuisine. Mint is also used in British and American cuisine for mint sauces and lamb dishes. Spearmint, peppermint, and applemint sprigs serve as garnish in drinks and fruit dishes. And also, to flavor alcoholic drinks like mint julep, mojito, and crème de menthe.
Safety aspects
When used as spices and other natural and seasonal flavorings, Mentha piperita L. (Peppermint) and Mentha spicata L. (Spearmint) are GRAS, according to 21 CFR 182.10 of the USFDA. Also, menthol from Mentha species, essential oils, oleoresins (solvent-free), and natural extractives (including distillates) from Mentha piperita L. (Peppermint) and Mentha spicata L. (Spearmint) are GRAS, according to 21 CFR 182.20 of the USFDA. Generally Recognized as Safe (GRAS) is a designation used by the U.S. Food and Drug Administration (FDA) to indicate that a substance added to food is considered safe by expert scientific community knowledgeable about the safety of substances added to food, and therefore, it is exempt from the usual Federal Food, Drug, and Cosmetic Act (FFDCA) food additive requirements.
Dried aqueous extract of spearmint containing 14.5% to 17.5% of rosmarinic acid was considered safe and well-tolerated when taken up to a dose of 900 mg/day for 90 days in a randomized, double-blind, placebo-controlled study involving subjects with AAMI.14
Conclusion
Mint has proven itself as a multifaceted herb, spanning from ancient traditional remedies to its modern scientific applications. As a vital crop, mint significantly contributes to global trade, with India standing as a major exporter of mint oils and menthol. Its cultivation is tailored to various climates, and its extensive applications range from FMCG products to pharmaceuticals, highlighting its economic and therapeutic value. Clinical studies indicate the mint’s potential health benefits in managing conditions like irritable bowel syndrome, cognitive performance, and knee osteoarthritis. Safety profiles support its status as a GRAS ingredient for its intended use, reinforcing its versatility and significance. Thus, mint can be considered a green gold with potential health benefits.
Disclaimer: The information provided in this write-up is for educational and informational purposes only. It is not intended as medical advice, diagnosis, or treatment. While the write-up discusses the traditional uses and clinical studies related to mint, individuals should consult healthcare professionals before using mint or its derivatives for medicinal purposes. The safety and efficacy of mint products can vary based on individual health conditions, and the use of mint in foods, cosmetics, and pharmaceuticals should comply with relevant regulatory standards and guidelines.
References
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10. Herrlinger KA, Nieman KM, Sanoshy KD, Fonseca BA, Lasrado JA, Schild AL, Maki KC, Wesnes KA, Ceddia MA. Spearmint extract improves working memory in men and women with age-associated memory impairment. J Altern Complement Med. 2018 Jan;24(1):37-47.
11. Akdoğan M, Tamer MN, Cüre E, Cüre MC, Köroğlu BK, Delibaş N. Effect of spearmint (Mentha spicata Labiatae) teas on androgen levels in women with hirsutism. Phytother Res. 2007 May;21(5):444-7.
12. Grant P. Spearmint herbal tea has significant anti-androgen effects in polycystic ovarian syndrome. A randomized controlled trial. Phytother Res. 2010 Feb;24(2):186-8.
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