About Rhoicissus rhomboidea (E.Mey. ex Harv.) Planch.
Rhoicissus rhomboidea (E.Mey. ex Harv.) Planch. is a vigorous evergreen plant that most often grows as a scrambling vine or liana, reaching 3 to 6 meters (6–20 feet) in height, but it can also develop into a small tree or shrub. Its leaves are dark green, rhombic, and trifoliate, made up of three asymmetrical leaflets borne on short stalks. The leaflets are leathery and satiny, covered in pale russet hairs on their lower surface, and have irregularly toothed margins. Each tooth ends in a point roughly 1 mm long, and the tip of each leaflet tapers gradually. The dark brown stem branches heavily, and bears very strong, forked tendrils. Young parts of the plant are covered in soft rust-colored hairs. This species is native to South Africa, Eswatini, Mozambique, and Zimbabwe. Within South Africa, it occurs in the Eastern Cape, KwaZulu-Natal, Mpumalanga, and Limpopo provinces, where it typically grows in forests and on forest edges. It adapts well to tropical, warm temperate, and subtropical climate zones. Rhoicissus rhomboidea is widely cultivated as a garden plant. It prefers cool, sheltered positions during summer, and requires winter warmth because it is damaged by frost. In gardens, it is grown on trellises, alongside staircases, at entrances, and in hanging baskets. It can be propagated from both cuttings and seeds. The plant produces edible grape-like fruits that attract birds, and the fruits are also eaten by humans. Its stems are used to make rope, which gives the plant one of its common names, 'ropewood'. It is rarely affected by pests or diseases, is tough, tolerates neglect, and can grow in poor conditions. It can be distinguished from the oak-leaved Cissus alata by its diamond-shaped (rhombic) leaves, though the two species have often been misidentified and their names misapplied. In folk medicine, the roots of this plant have been used to aid childbirth for pregnant people. Extracts of the plant have demonstrated a 56% inhibition of prostaglandin synthesis, compared to 89% inhibition achieved by the standard drug indomethacin, indicating potential use as an anti-inflammatory agent. The plant shows some antimicrobial activity, with root extracts showing the greatest inhibitory activity against a range of microorganisms. Stem extract, along with the standard antibiotics chloramphenicol and tetracycline, all produced measurable inhibition zones against Salmonella sp. Aqueous and methanol extracts of the plant have been tested for potential anticancer therapeutic activity: in vitro testing measured antiproliferative activity against the human liver cancer HepG2 cell line. The plant contains polyphenol compounds with strong radical-scavenging and antiradical activity. Its extracts show more than 50% antioxidant activity compared to commercial antioxidant standards, and achieved roughly 98% radical scavenging activity against the 1,1-Diphenyl-2-picrylhydrazyl free radical. Root extract of the plant inhibits xanthine oxidase by 88.20%.
