Black Turmeric

A relative of turmeric (the golden spice), this deep blue rhizome has its own unique health-boosting value and history in medical traditions.

Black turmeric (Curcuma caesia) rhizomes. Image source.

Many are familiar with the bright orange turmeric (Curcuma longa), but its dark blue kin, black turmeric, might be new to you. This perennial herb, Curcuma caesia, is part of the ginger family and is native to the Himalayas and Southeast Asia. Its distinctive leaves have a violet-red stripe, and the bluish-black rhizome is central to many traditional medicinal practices. However, this plant is at risk due to human activities, diseases, and habitat destruction. Modern methods like in vitro cell and tissue culture are being employed for its conservation. Dive deeper with me as I explore the history, chemistry, and medicinal potential of black turmeric.

Botanical Origins

Leaves (left) and stalk + rhizome (right) of Curcuma caesia. Image source.

Black turmeric (scientific name: Curcuma caesia) is a perennial herb from the ginger (Zingiberaceae) family is recognized by its bluish-black rhizome. Known by the common names of kali haldi (Hindi), black turmeric (English), and kunyit hitam (Malaysia), this plant originates in the Himalayan region in India and South East Asia. Its leaves feature a striking violet-red stripe down their length. The leaf's upper surface is typically rough and velvety, though this can vary. The herb's green bracts have a hint of rust, while its flower petals can be deep pink or red. The rhizome itself has a bitter, pungent flavor and aroma.

Unfortunately, black turmeric is under threat due to factors like human usage, low multiplication rates, disease, and habitat destruction from industrialization. Traditional propagation methods present challenges such as disease transfer, seed preservation, and resource consumption. To combat extinction, researchers are employing in vitro cell and tissue culture methods for conservation, offering benefits like disease-free plants and efficient multiplication.

Traditional Medicine

Black turmeric is important in traditional medicine, especially in India. The rhizome, enriched with aromatic chemical compounds, serves as the primary part used for its medicinal properties. Its potency as a stimulant and carminative agent has earned it widespread recognition in various cultures and practices. A review paper on this plant compiled evidence from the literature on its traditional uses. Here are just a few examples of how the rhizome is used in traditional medicine:

• Antivenom: The paste from the rhizome is traditionally used as a remedy for snake and scorpion bites.

• Cosmetic Use: Women apply powdered rhizomes as a facial mask during engagement and wedding ceremonies.

• Digestive and Reproductive Health: Mixed with honey or milk, it's consumed for ailments like weakness, infertility, irregular menstrual cycles, and bloating. It's also taken with water for stomach aches.

• Pain and Inflammation: The fresh rhizome is mashed into a paste which is applied to sprains, bruises, and used as a migraine reliever.

• Rubefacient: The Turkomans use the rhizomes as rubefacients, applying them to their bodies after Turkish baths.

Rubefacient: A substance that, when applied to the skin, increases blood circulation and causes the skin to become redder. This can produce a warming or burning sensation on the skin. Rubefacients are often used in liniments and ointments to relieve muscle and joint pain.

Pharmacology

Chemistry

The distinctive properties of black turmeric stem from specialized compounds known as curcuminoids, primarily found in the rhizomes. Curcuminoids, fat-soluble polyphenolic pigments, play a central role in turmeric's applications as spices, pigments, and therapeutic agents. The primary component is curcumin, followed by desmethoxycurcumin, bisdemetoxycurcumin, and cyclic curcumin.

Read more about the health benefits of curcumin and related curcuminoids in my earlier post on turmeric and pain.

Lab Studies

There have been many laboratory studies conducted on black turmeric rhizomes. In most of these, tests were performed in test tubes or in mice using extracts of the rhizome. Here are some of the major findings highlighted in the scientific literature:

• Analgesic: It possesses analgesic properties that relieve pain through various mechanisms, exhibits anticonvulsant, muscle relaxant, and locomotor depressant activities, and influences the central nervous system as observed in multiple rodent studies.

• Antibacterial: It exhibits antibacterial properties against several bacteria, including Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Diplococcus pneumoniae, Streptococcus pyrogens, Micrococcus glutamicum, Serratia marcescens, Staphylococcus epidermidis, Proteus vulgaris, Klebsiella pneumoniae, Salmonella typhimurium, and Mycobacterium tuberculosis.

• Anticancer: It exhibits anticancer properties, evidenced by its ability to reduce tumor growth, enhance antioxidant activity, counteract chemotherapy-induced toxicity, and inhibit liver carcinoma cell proliferation.

• Antidiabetic: It exhibits antidiabetic effects by reducing blood glucose levels, inhibiting key enzymes, and enhancing glucose uptake in cells, with various extracts showcasing significant antidiabetic and antioxidant properties.

• Antifungal: It demonstrates antifungal activity, notably against fungal species including Aspergillus flavus, Fusarium oxysporum, Botrytis cinerea, Rhizopus oryzae, Aspergillus fumigatus, Aspergillus niger, and Candida albicans.

• Anti-inflammatory: It has demonstrated significant anti-inflammatory properties by selectively inhibiting COX-2, reducing mouse paw edema, and displaying albumin denaturation inhibition activity superior to standard treatments.

• Antioxidant: It scavenges reactive oxygen and nitrogen species, exhibiting protective effects against oxidative stress in both in vitro and in vivo models.

Clinical Studies

I found one human study on black turmeric. It compared the effectiveness of black turmeric and standard steroid therapy in treating Oral Submucous Fibrosis (OSMF), 42 participants were divided into two groups. Group A used a mix of Kali Haldi (black turmeric) powder and aloe vera gel, while Group B was treated with hydrocortisone injections and oral antioxidants. After three months, both treatments showed significant improvement, with Group A exhibiting more noticeable symptom relief. The study suggests that the combination therapy, which incorporates an ancient ayurvedic regimen, could be a safer and equally effective treatment for OSMF, meriting further research with larger samples and extended durations.

The Takeaway

Black turmeric is a medicinal plant with a wide range of traditional uses, and laboratory studies have supported its potential medical applications. However, there is very limited clinical evidence regarding its safety and efficacy in humans, necessitating further research. Moreover, concerns exist about the wild-harvested rhizomes, as the plant faces threats from pests, habitat changes, and human consumption. Given its significant potential, conservation efforts are crucial to guarantee its continued availability.

Yours in health, Dr. Quave

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Cassandra L. Quave, Ph.D. is a scientist, author, speaker, podcast host, wife, mother, explorer, and professor at Emory University School of Medicine. She teaches college courses and leads a group of research scientists studying medicinal plants to find new life-saving drugs from nature. She hosts the Foodie Pharmacology podcast and writes the Nature’s Pharmacy newsletter to share the science behind natural medicines. To support her effort, consider a paid or founding subscription, with founding members receiving an autographed 1st edition hardcover copy of her book, The Plant Hunter.

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