Tulbaghia violacea / Kaapse knoflook
1.1. Source and History
Tulbaghia violacea is an African herb used historically to treat some infectious diseases, which is due to an anti-microbial potential of the herb. The herb appears to be synergistic with itself in this regard, suggesting that multiple components within the herb itself work together.
It belongs to the Alliaceae family of herbs, similar to Garlic. It is sometimes referred to as Sweet Garlic (as its consumption is not associated with bad breath), Wild Garlic, or Society Garlic and possesses a strong garlic odour, although the roots are sometimes referred to as skunky. It is also referred to as 'Isihaqa' by the Zulus, who use this plant as an aphrodisiac, and as 'Wildeknoffel' by the Afrikaans. It may share nutrient motifs with the garlic family. It is referred to as a modest, unassuming plant with small flowers and grassy foliage.
As a herbal supplement, Tulbaghia violacea may contain a wide variety of compounds. Some of these compounds include:
3 Cysteine derivates known as Marasmin, Ethiin and Methiin
From the leaves, 2,4,5,7-tetrathiaoctane-2,2-dioxide, 2,4,5,7-tetrathiaoctane, and 2,4,5,7-tetrathiaoctane-4-oxide
Compounds that are inherent to the Allium (Garlic) family, and show motifs with Tulbaghia (in regards to traditional usages and preparation) include (note, it is plausible but not assured Tulbaghia contains these molecules):
Cysteine Sulfoxide derivatives (Alliin, Isoalliin, and Methiin) found in both onions and garlic These compounds have been reported in T.Acutiloba.
Of the Tulbaghia family of herbs, violacea appears to have the highest known concentration of sulfur-containing compounds (although not all species have been analyzed).
2 Interactions with Cardiovascular Health
2.1. Blood Pressure
Tulbaghia Violacea appears to have ACE inhibiting properties, reaching 68% ACE inhibition with the water extract and 71% with the ethanolic extract in vitro. When rats were subject to 0.1mg/kg Angiotensin I injections (increasing the control groups blood pressure by 14.5%) co-injection of 50mg/kg bodyweight Tulbaghia Violacea was able to attenuate the increase to 2.2%, showing bioactivity.
Tulbaghia Violacea has been shown in a model of spontaneously hypertensive rats to reduce both systolic and diastolic blood pressure, as well as heart rate, by acting as a ACE inhibitor. It may also have interactions with B(1)adrenoreceptors.
3 Interactions with Carbohydrate Metabolism
Tulbaghia Violacea has been implicated in exerting anti-diabetic effects in vitro, by increasing glucose uptake by 140.5% in muscle cells at a concentration of 0.5ug/mL with the ethanolic extract. The water extract increased glucose uptake by 119% at this concentration, and uptake was increased by approximately 117% by both extracts at a concentration of 50ug/mL, although insulin incubation at 0.5ug/ml seemed to reduce glucose uptake induced by T.Violacea.
4 Interactions with Testosterone
One in vitro study conducted on testicular cells noted that the extract of Tulbaghia violacea was able to increase testosterone release from testicles in response to stimulation from Luteinizing Hormone. The cells were incubated at varying concentrations ranging from 156.25-5000ug/ml at doubling intervals and, although only showing statistical significant at a concentration of 312.5ug/ml and above, did not show any dose-dependent effects but rather constant elevation of testosterone secretion. The increases in testosterone were quantified to be 30-72% greater than control cells, and was dependent on the presence of lutenizing hormone. No direct testicular increases in estradiol were noted.
5 Safety and Toxicity
Historically, it has been noted that prolonged and excessive use of Tulbaghia Violacea bulbs causes gastrointestinal distress and may be associated with acute inflammation and sloughing of intestinal tissue as well as cessation of peristalsis. Contraction of the pupils and delayed response to stimuli have been mentioned additionally.
Scientific Support & Reference Citations
Ncube B, Finnie JF, Van Staden J In vitro antimicrobial synergism within plant extract combinations from three South African medicinal bulbs . J Ethnopharmacol. (2012)
Raji IA, Mugabo P, Obikeze K Effect of Tulbaghia violacea on the blood pressure and heart rate in male spontaneously hypertensive Wistar rats . J Ethnopharmacol. (2012)
Ebrahim M, Pool EJ The effect of Tulbaghia violacea extracts on testosterone secretion by testicular cell cultures . J Ethnopharmacol. (2010)
Burton SG, Kaye PT Isolation and Characterisation of Sulphur Compounds from Tulbaghia violacea . Planta Med. (1992)
Kubec R, Velísek J, Musah RA The amino acid precursors and odor formation in society garlic (Tulbaghia violacea Harv.) . Phytochemistry. (2002)
Ramesar S, et al Angiotensin I-converting enzyme inhibitor activity of nutritive plants in KwaZulu-Natal . J Med Food. (2008)
Duncan AC, Jäger AK, van Staden J Screening of Zulu medicinal plants for angiotensin converting enzyme (ACE) inhibitors . J Ethnopharmacol. (1999)
van Huyssteen M, et al Antidiabetic and cytotoxicity screening of five medicinal plants used by traditional African health practitioners in the Nelson Mandela Metropole, South Africa . Afr J Tradit Complement Altern Med. (2011)
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Taylor MJ1, et al Folate for depressive disorders . Cochrane Database Syst Rev. (2003)
Godfrey PS1, et al Enhancement of recovery from psychiatric illness by methylfolate . Lancet. (1990)
Kushwaha S1, Chawla P1, Kochhar A1 Effect of supplementation of drumstick (Moringa oleifera) and amaranth (Amaranthus tricolor) leaves powder on antioxidant profile and oxidative status among postmenopausal women . J Food Sci Technol. (2014)