| Botany
Ligas is a small tree growing to a height of
12 meters. Leaves are crowded at the end of the branches, lanceolate-obovate
to oblong-obovate, 10 to 25 centimeters long, hairy, whitish beneath, rounded or
somewhat pointed at the tip and usually pointed at the base. Flowers
are whitish, 2 to 2.5 millimeters long, borne on panicles that are longer than
the leaves. Fruits are borne in clusters, resembling the kasui, but
much smaller. Drupe is ovoid, oblique, 1 centimeter long, grows at the top of
a red or purple, fleshy and edible fruit, which is about as long as the drupe. The "fruit," like that of the kasui, is really the enlarged
stalk and receptacle (torus) of the flower.
Distribution
- Common in dry thickets and secondary forests at low altitudes in Cagayan, Ilocos Norte, Bontoc, La Union, Pangasinan, Zambales, Bataan, Nueva Ecija, Rizal, Pampanga, Bulacan, Laguna, Quezon and Sorsogon Provinces in Luzon; and in Mindoro, Palawan, Leyte, Negros, and Guimaras.
- Also reported in Indonesia.
 Constituents
- Cardol is the toxic principle of the
sap found in the bark and fruit.
- Phytochemical study yielded biflavoinoids, phenolic compounds, bhilawanols,
minerals, vitamins and amino acids.
- Nut of the shell contains biflavonoids, biflavones, tetrahydrorobustaflavone, jeediflavone, semecarpuflavone and gulluflavone.
- Oil from the nuts contain bhilavinol.
- Leaves contain amentoflavone.
Properties
- Oil of pericarp is caustic and escharotic.
- Fruits are considered acrid, bitter, astringent, thermogenic, emollient, digestive, carminative, purgative, liver tonic, aphrodisiac, antiarthritic, depurative, anti-inflammatory, cardiotonic, sudorific.
- Oil considered to have antioxidant, anticancer, and anti-inflammatory properties.
Caution !
- Although many persons are probably immune to poisoning from the hairs on the leaves, in the Philippines the plant is usually regarded as poisonous, with reports of severe contact dermatitis.
- The sap is considered a violent contact poison which can cause painful swelling and minute blistering pustular skin eruptions.
- Allergic Contact Dermatitis: Study showed uroshiol to be the active allergen in seeds. (see study below) (28)
Parts utilized
Leaves, fruit, gum.
Uses
Folkloric
• Oil of pericarp is used as
a caustic or escharotic; sometimes used for indolent ulcers.
• In Malaysia, leaves
used for wounds.
• In India, fruit is traditionally used as folk remedy for the treatment of non-bleeding hemorrhoids. Also used as adjuvant treatment for ascites and tumors. Used for bronchospasm.
• Elsewhere, the gum-resin of S. anacardium has been used in leprosy
and nervous debility.
Others
• Teeth dyeing: Resin from bark and pericarp used for teeth blackening.
 Studies
• Quisumbing lists Semicarpus cuneiformis and S. anacardium
as scientific synonyms. Studies below are mostly on Semecarpus anacardium. Other compilations separate the species. Both can cause acute and extensive dermatitis.
• There are no published studies on Semicarpus cuneiformis.
• Antioxidant / Antiarthritic:
Milk extract of Semecarpus anacardium nuts significantly decreased the
lipid peroxide levels in plasma and tissues of adjuvant arthritis.
The SA nut extract brought back the altered antioxidant defense components
to almost normal levels. The antiarthritic effect may be due to the
retardation of lipid peroxidation and a subsequent modulation of the
cellular antioxidant defense system. (1)
• Antioxidant / Prooxidant:
Nut purification studies suggested that the oil part of the nuts is
prooxidant whereas the alcoholic fraction is antioxidant; and the use
of hexane is better for purification of SA nuts and therapeutic enhancement.
• Antiinflammatory:
(1) Studies have yielded phenolic compounds (semicarpol and bhilawanol)
found to inhibit the acute tuberculin reaction in sensitized rats and
primary phase of adjuvant arthritis. IN rheumatoid arthritis, inflammatory
activity has been attributed to flavonoids or the inhibition of early
mediator release (histamine and serotonin) and inhibition or cyclo-oxygenase. (2) Study of extract of SA demonstrated a protective immunological and pharmacological role.
• Antifungal:
Alcoholic extract of dry nuts of SA showed dose-dependent antifungal
activity against Aspergillus fumigatus and C albicans.
• Neuroprotective:
SA has been shown to have neuroprotective effect, especially to the
hippocampal region in stress-induced neurodegeneration like Alzheimer's
disease.
 • Antispermatogenic Effect:
SA extract feeding caused antispermatogenic effect with reduction in
the numbers of spermatogenic cells and spermatozoa.
• Antiatherogenic:
The antiatherogenic effect may be due to its antioxidant, anticoagulant,
hypolipidemic, anti-platelet aggregation and lipoprotein lipase releasing
properties.
• Hypoglycemic:
Ethanolic extract shown to significantly lower blood glucose level in
alloxan induced diabetic rats.
• Toxicity Studies:
Acute toxicity studies showed no mortality at all dose levels. Subacute toxicity studies showed not hematologic and biochemical alterations; in the highest dose, there was a moderate increase in blood sugar; histopath exam showed no morphological disturbances.
• Cardioprotective / Fruits: Study on the bioactivity in the ethanolic extract of SA fruits on experimentally induced myocardial damage in rats showed high dose of EESA significantly reduced endogenous biomarker enzymes, with significant increase in biological antioxidants and catalase activities, while providing significant recovery from ischemia.
• Antioxidant / Anticarcinogenesis:
Administration of aqueous extract of SA to lymphoma-transplanted mouse caused an increase in antioxidant enzyme activities, with significant decrease in LDH activity, indicating decrease in carcinogenesis. The extract effect was more than doxorubicin, an anticarcinogeic drug.
• Hypoglycemic / Antihyperglycemic Effect:
Ethanolic extract of dried nuts of SA showed reduction of blood glucose in normal rats and also significantly lowered blood glucose in STZ-induced diabetic rats. Antihyperglycemic effect was compared with tolbutamide.
• Anti-Tumor / Anti-Hepatocellular Carcinoma:
Study was done to evaluate the effect of Semecarpus anacardium nut extract on the hepatocarcinogenicity of aflatoxin B1 in adult albino male Wistar rats. Results clearly showed antitumor efficacy of SA nut extract on aflatoxin B1-induced hepatocellular carcinoma.
• Anti-Inflammatory / COX-2 Inhibitory Activity:
Extract of the bark stem of SA showing in vitro anti-inflammatory activity in carrageenan induced rat paw edema was studied to identify its active compounds. The study yielded 2 compounds – butein and a trihydroxyflavone. The compounds showed moderate COX-2 inhibitory activity. (13)
• Reproductive Effects / Spermatogenic Arrest:
S. anacardium fruit extract administration resulted in spermatogenic arrest in albino rats. Sperm motility and density were significantly reduced.
• Toxicological Study of Anacardium Nut Extract:
Toxicological study on S. anacardium nut extract was done to determine its safe non-toxic dose. Toxicity was found to be dose-dependent. Results could be of some use in cancer chemotherapy study of the fraction. (16)
• Analgesic / Stem Bark: Study investigated the analgesic effect of various extracts of Semecarpus anacardium by tail flicking and writhing methods. A methanol extract showed more significant analgesic activity compared to petroleum ether and chloroform extracts. All extracts were less potent than the standard drug acetyl salicylic acid. (18)
• Cytoprotective: Study investigated the cytoprotective effect of S. anacardium in rats rendered diabetic by streptozotocin. Results showed cytoprotective effect with reversal of marker enzymes in the serum, liver, and kidney. (19)
• Antioxidant / Nuts: Study investigated the in vitro antioxidant activity of various extracts of nuts by non-enzymatic haemoglobin glycosylation and DPPH free radical scavenging activity. Results showed concentration dependent antioxidant activity, with the ethanol extract showing higher antioxidant activity than the other extracts. (20)
• Cardioprotective / Propranolol-Isoproterenol Interaction / Nuts: Study evaluated the cardioprotective effect of an ethanolic extract of SA nuts and possible interaction with propranolol against isoproterenol induced myocardial damage in female Sprague-Dawley rats. Results showed the combination of high dose of S. anacardium with propranolol was most effective in alleviating the abnormal conditions induced by isoproterenol. (21)
• Antioxidant / Nuts: Study evaluated the anticancerous efficacy of an Ayurvedic preparation made from S. anacardium nuts on rats with hepatocellular carcinoma induced by N-nitrosodiethylamine. The Ayurvedic drug showed a positive correlation with the action of doxorubicin. Study demonstrated the efficacy of the nut extract for treatment of hepatocellular carcinoma either alone or with chemotherapy. (22)
• Anti-Inflammatory / Fruits: Study of aqueous extract of S. anacardium fruits in albino rats showed significant anti-inflammatory effect compared to reference drug indomethacin. (23)
• Aphrodisiac Activity/ Nuts: Study explored the effect of S. anacardium nuts on sexual function of normal male mice. Results showed enhanced sexual behavior in male mice with increased mounting behavior and significantly increased mating performance. (24)
• Treatment of Oral Submucus Fibrosis: OSMF is associated with juxtaepithelial inflammatory reaction with fibroelastic changes in the lamina propria which leads to stiffness of the oral mucosa. A hydroalcoholic gel formulated using Semecarpus anacardium showed promising effects on different parameters of OSMF. (25)
• Effect of Oil Extract on Brain Physiology: Ancient literature has reported ill effects of indiscriminate use of nut oil on skin and eyes. Labours in rural areas involved in extraction of oil were found to suffer from deformities due to exposure. Study assessed the effect of SA pericarp oil extract on biochemical parameters of GOT, GPT, LDH, SDH and AChE enzymes of brain of albino rat. Study showed alterations in studied parameters indicating adverse effects. Results signify the need of safe work environment, safer extraction process and proper training of workers. (26)
• Nootropic Activity / Milk Extract: Study evaluated the effects of nuts extracted with milk on the CNS for locomotor and nootropic activities. No significant alteration was noted in locomotor activity. In experimental amnesia models, the extract showed statistically significant nootropic activity. (27)
• Allergic Contact Dermatitis / Burning of Seeds for Evil Eye / Urushiol: In India, a ritual for evil eye protection is done by burning SA seeds. The smoke produced by burning seeds can cause contact dermatitis over time. Study showed uroshiol to be the active allergen in SA seeds responsible for the allergic contact dermatitis from exposure to smoke from burning of seeds. (28)
Availability
Cultivated.
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