Page 28 - FoodFocusThailand No.158 May 2019

SCIENCE & NUTRITION
SCIENCE & NUTRITION

Sour Leafy Plants:
Local Vegetables

with High Medicinal

Benefits in their Leaves

Consuming healthy Thai foods, such as foods
rich in vegetables and herbs, is one of the
alternative pathways to reduce the risk of
non-communicable diseases.

These vegetables contain a variety of nutrients, especially vitamins a source of antioxidant, which is corresponded to the function of
such as vitamin A, B, C, E, and minerals, which are essential for growth chlorogenic acid .
[11]
and balance in various systems of the body. Besides, Thai food has
unique taste, each of which comprises of 2-3 flavors mixing together, Tamarindus indica L. is a tree in the Caesalpiniaceae family.
resulting in a balance of taste. Missing one of the flavors can cause the T. indica contains high contents of tartaric acid and reducing sugars,
taste to be distorted. For example, the taste of sour curry is a combination essential oils, free and conjugated fatty acids, flavonoid glycosides
of sour, sweet and spicy. Sour taste can be obtained from lemon juice (vitexin, isovitexin, orientin and isoorientin) and other components
and tamarind juice due to high amount of vitamin C. Some vegetables [12] . Tamarind fruit is often used for cooking for its sour taste. Fruit and
also have a sour taste; however, this is a result of high amount of organic seeds possess anti-microbial activity, increase digestion, support
acids. Normally, these vegetables are boiled and blended with chili paste, laxative effect, control diabetes and improve immune system . In
[13]
such as leaves of Cratoxylum formosum (Jack.) Dyer and Syzygium addition, tamarind extract had been reported to contain high level of
gratum (Wight) S.N. Mitra. Some sour leafy vegetables are used as a polyphenols, resulting in reduced arteriosclerosis in rat model and
component in recipes for sour taste such as pork curry, chicken spicy increase antioxidant properties [14] . Young leaves of T. indica can
soup with young shoot of tamarind leaves and spicy salad with Spondias sometimes be employed as sour ingredient instead of lemon and
pinnata (Linn.f.) Kurz leaves. These sour leaves provide a unique, sour were found to possess antioxidant activity, anti-inflammatory activity,
taste with health benefits. antinociceptive activity and anti-apoptotic and hepatoprotective
effects .
[13]
Garcinia cowa Roxb. (local names as Cha-Muang, Ka-Muang,
Muang-Som, Som-Pong and Mak-Mok) is in the Family Guttiferae or Spondias pinnata (Linn.f.) Kurz (Thai local name of Makok)
Clusiaceae with a shape of shrubs or polygamous trees of around 5-10 in the Anacardiaceae family is a deciduous tree with a height of 15-30
cm of height. This plant possesses a rich source of secondary metabolites meters when fully grown. Several bioactive compounds from the
including prenylated xanthone, acylphloroglucinol derivatives, flavanone isolation of this tree include flavonoids, glycosides, alkaloids,
glycosides, benzophenones, hydroxycitric acids and phenolic acids [1-4] . carbohydrates, saponins, steroids and gums. Interestingly, gums from
These bioactive compounds possess a wide range of biochemical and S. pinnata are acidic polysaccharides, forming bonds with β-amyrin,
pharmacological activities. The most widely investigation on this plant oleanolic acid or some amino acids . The crude extract from the
[15]
has been emphasized on antibacterial and fungal properties. It was plant possesses various medicinal properties including function
found that G. cowa exhibits an antimicrobial function against against dysentery, antibacterial activities, central nervous system
Staphylococcus aureus (food poisoning), Plasmodium falciparum depressant effect, diuretic and laxative activity as well as anti-
(malarial parasite), Aspergillus flavus (aflatoxin production), tubercular properties. S. pinnata is also a potential source of natural
Pseudomonas aeruginosa (drug resistance) and phytopathogenic antioxidant with no significant toxicity being observed .
[16]
fungi [5-6] . Besides, G. cowa also possesses cytotoxic effect toward cancer
cell lines, improves blood circulation and relieves fever . These Syzygium gratum (Wight) S.N. Mitra. (Thai local name of
[7]
properties are the results of its xanthone with phenolic functional groups Meg, Kai-Meg, Yee-Meu-Lea, Samed, Samed-Kwaw, Samed-Deang
that exhibit antioxidant properties. and Meg) in the Myrtaceae family is a medium sized tree of around
20 meters tall. Regardless of its little information on isolated bioactive
Cratoxylum formosum (Jack.) Dyer (local names as Kui- compounds from this plant, its biological property towards medicinal
Chung, Kui-Chong-Chao, Taw, Tew-Daeng, Tew-Yang, Tew-Laud, Tew- values of the crude extract was found to possess high antioxidant
Leung, Teaw and Teaw-Hin) is in the Clusiaceae family, which is found activities . The plant was hypothesized to exhibit none to less toxicity
[10]
in all mixed deciduous forests. Its bioactive compounds consist of since locals can daily consume this plant. Hence, its crude extract
xanthones, flavonoids and anthraquinones . C. formosum had been was examined against β-thalassemia/HbE in patients [17] as well as
[8]
reported to possess several medicinal properties. Leaves of C. formosum investigated antioxidant defense system in mice .
[18]
were found to function against liver cancer cell line as well as possess
antiviral activity, antimicrobial activity, antimutagenicity, vascular and
gastric protective effects [9-10] . Besides, it was found that this plant provides
28 FOOD FOCUS THAILAND MAY 2019

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