Gen info
- Olax is a plant genus in the family Olacaceae, which contains fifty-three species.
- Etymology: The genus name derives from Latin olax, meaning "malodorous", referring to the unpleasant scent of some Olax species.
- Some species have leaves and fruits smelling of garlic such as Olax subscorpioidea and O. gambecola.

Botany
• A climbing shrub, growing up to 2-6 m tall. Vine stem diameter to 5 cm. Leaf blades about 8.5-11 x 3.5-5 centimeters, petioles about 5 millimeters long, broad but not winged. Lateral veins forming loops inside the blade margin. Inflorescences many-flowered. Calyx very small. Petals linear-oblong, about 10-12 millimeters long. Stamens 3, staminodes 5 or 6, bifid. Fruits globular, about 2.5-3 centimeters diam. Seeds about 1.8 x 1.8 centimeters. Embryo located near the apex of the seed. Embryo small, about 2 millimeters long, swollen about the middle. Cotyledons about as wide as the radicle. (3)

• Shrubs, sometimes climbers, 2-6 m tall. Branchlets brown. Petiole 5-10 mm; leaf blade elliptic to ovate-oblong, 5-10 × 2.5-3.5 cm, ± leathery, glabrous, base rounded, apex acute; secondary veins 6-9 on each side of midvein. Inflorescences usually unbranched, 1.5-2.5 cm; rachis zigzagged; peduncle 3-10 mm. Pedicel 1-3 mm. Calyx small, truncate. Petals white or yellowish, 8-10 mm, 1 entire and 2 2-lobed. Style to 1 cm. Drupe ± globose or obovoid, nearly covered by accrescent orange calyx, 1.5-2 cm in diam. (Flora of China)

Distribution
- Native to the Philippines.
- In primary and secondary forests, in dry brushwood, on coral limestone, and occasionally in mangrove or peat swamp, up to 900 m altitude. (1)
- Also native to Andaman Is., Bangladesh, Borneo, Cambodia, Caroline Is., Hainan, India, Jawa, Lesser Sunda Is., Malaya, Maluku, Myanmar, New Guinea, Nicobar Is., Solomon Is., Sulawesi, Sumatera, Taiwan, Thailand, Vietnam. (2)

Constituents
- Study of methanol extract of plant isolated three triterpenoid glycosides viz., 3-O-a-L-rhamnopyranosyl-(1->4)-b -D-glucopyranosyl-(1->3)-6′- O-ethyl-b-D-glucuronyl oleanolic acid (1), oleanolic acid 28-O-b -D-glucopyranoside (2) and spergulacin (3). (see study below) (6)
- Study of methanol extract of roots isolated one new sesquiterpenoid tropolone and three new 1,2,3,4-tetrahydronaphthalene derivatives, olaximbrisides A–D (1–4). (see study below) (9)

Properties
- Studies have suggest antidiabetic, anti-obesity, hypolipidemic, anticancer, antimicrobial properties.

Parts used
Bark, roots, leaves.

Uses
Edibility
- Fruit is edible.
Folkloric
- Ethnic people in Gingee Hills, Tamilnadu, India use the bark for treatment of anemia and diabetes. (7)
- Bark and roots used for treating diarrhea, ulcers, and inflammation.

Studies
• Control of Obesity, Blood Glucose and Lipids / Toxicity Study / Roots: Study evaluated the effects of n-hexane extract of roots on obesity, blood glucose, and blood lipid in high-fat diet-induced obese mice. Three months of daily use of 5000 mg/kbw (equivalent to 350 g/d for a 70 kg person) showed no mortality nor abnormalities. After 6 weeks at 500 mg/kbw, there was a positive effect evidenced by significant reduction in glycemic index and body weight of tested mice, reduced triglycerides, total cholesterol, TC/HDL, LDL/HDL index, increase in HDL, along with histopathological studies of white adipose, liver, kidney tissues as well as locomotion activity. (5)
• Antidiabetic / α-Glucosidase Inhibitory Activity / Triterpenoid Glycoside: Study of methanol extract of plant isolated three triterpenoid glycosides viz., 3-O-a-L-rhamnopyranosyl-(1->4)-b -D-glucopyranosyl-(1->3)-6′- O-ethyl-b-D-glucuronyl oleanolic acid (1), oleanolic acid 28-O-b -D-glucopyranoside (2) and spergulacin (3). Compound 2 exhibited strong alpha-glucosidase inhibitory activity with IC50 of 56.15 mM, suggesting antidiabetic potential. (6) 
• Antimicrobial / Leaves: Study screened various leaf extracts of Olax imbricata for antibacterial and antifungal activity using agar disc diffusion and well diffusion method. Ethanolic leaf extract showed potent inhibitory activity against Gram-positive S. aureus, S. faecalis and Gram-negative V. cholera, P. aeruginosa, K. pneumonia, and P. vulgaris. The aqueous extract showed maximum activity against all tested bacteria. Methanol and ethanol extracts showed high antibacterial activity. (Sagayaraj and Britto, 2014) (8) 
• Cytotoxicity / MCF-7 and HepG2 Cancer Cell Lines / Roots: Study of methanol extract of roots isolated one new sesquiterpenoid tropolone and three new 1,2,3,4-tetrahydronaphthalene derivatives, olaximbrisides A–D (1–4). Compound 1 exhibited cytotoxicities against MCF-7 and HepG2 and LU cell lines with IC50s of 16.3, 34.3 and 8.0 µM, respectively. (9)

Availability
Wild-crafted.

Additional Sources and Suggested Readings
(1)
Olax imbricata (PROSEA) / PCM Jansen, J Jukema, LPA Oyen, TG van Lingen / Pl@ntUse
(2)
Olax imbricata / KEW: Plants of the World Online
(3)
Olax / Wiikipedia
(4)
Olax imbricata Roxb. / Dr N Sasidharan / India Biodiversity Portal
(5)
Control of Obesity, Blood Glucose, and Blood Lipid with Olax imbricata Roxb. Root Extract in High-Fat Diet-Induced Obese Mice / Thi Nga Vo, Thi-Diem-My Luong, Thi-Phuong-Hoa Le, Khanh Son Trinh / Journal of Toxicology, 2022; Article ID 7781723 / DOI: 10.1155/2022/7781723
(6)
Triterpenoid Glycosides from Olax imbricata / Nga Thi Vo, Suong Thi Minh Huynh, Huong Thhi My Nguyen, Huy Thuc Duong, Phung Kim Phi Nguyen / VNUHCM Journal of Science and Technology Development, 2019; 22(3): pp 324-334 / DOI: 10.32508/stdj.v22i3.1660
(7)
An Ethnobotanical Study of Medicinal Plants Used by Ethnic People in Gingee Hills, Villupuram District, Tamilnadu, India / M Thamacin Arulappan, S John Britto, K Ruckmani, R Mohan Kumar / American Journal of Ethnomedicine
(8)
Pharmaceutical properties of genus Olacaceae: A Review  / Sirisha M.V.P.L.P, Sandhya Deepika / Advances in Animal Sciences, Theriogenology, Genetics, and Breeding, 2022; 10(1): pp 28-31 /
DOI: 10.51268/2736-1810-22.10.057
(9)
A sesquiterpenoid tropolone and 1,2,3,4-tetrahydronaphthalene derivatives from Olax imbricata roots / Huong T M Nguyen, Nga T Vo, Suong T M Huynh, Lien T M Do, Phung K P Nguyen et al / Fitoterapia, 2019; Vol 132: pp 1-6

DOI: It is not uncommon for links on studies/sources to change. Copying and pasting the information on the search window or using the DOI (if available) will often redirect to the new link page. (Citing and Using a (DOI) Digital Object Identifier)