1272

12(2): Medicinal and poisonous plants 2

Quassia L.

Sp. pl. ed. 2, 1: 553 (1762); Gen. pl. ed. 6: 212 (1764).

SIMAROUBACEAE

x = unknown; Quassia amara: 2n = 36

Major species Quassia amara L., Quassia indica (Gaertner) Noot.

Bitter wood (En). Malaysia: kayu pahit.

Quassia comprises about 40 species; it has a pantropical distribution, with its major centre of diversity in South and Central America. Two species are found in Burma (Myanmar) and Indo-China; Quassia indica extends from India eastward to the Solomon Islands. Quassia borneensis Noot. is confined to Borneo and Sumatra, and 2 species are native to Australia. Quassia amara is cultivated in many parts of Malesia and is locally naturalized.

Quassia amara is cultivated throughout the tropics for its medicinal properties and as an ornamental. Whereas the medicinal use of Quassia amara is limited to its wood, all parts of Quassia indica are used medicinally. Quassia in decoction or as an infusion is considered a general tonic, a febrifuge and a cure for intestinal disorders in various parts of the world. An extract of the plant or seed is used as an insecticide. Extracts of Quassia amara bark are sometimes employed as a general bitter in digestive tonics, liqueurs and beer. Furthermore, Quassia or preparations containing its bitter principle quassin are used to denature alcohol. In Sarawak, the wood of Quassia indica is used for making handles of knives. The purified oil from the seeds can be used for illumination as a lubricant and for the manufacture of soap.

In general, all plant parts are exceedingly bitter. The quassinoids comprise the most important group of compounds isolated; in the case of Simaroubaceae these are sometimes also known as simaroubolides. The principal basic skeleton of these decanotriterpenes (C₂₀) is that of picrasan-16-one. In addition, the quassinoids differ in the positions of double bonds, hydroxy-, epoxy-, oxo- and/or ester-groups (often with acetic- or C₅-acids, e.g. hydroxybutyric, isovalerenic). Examples are quassin (= nigakilacton D), isoquassin (picrasmin), neoquassin and quassinol. Other components isolated belong to 2 categories of indole alkaloids: the 'BETA'-carbolides (e.g. 1-vinyl-4,8-dimethoxy-'BETA'-carbolin) and the canthin-6-ones (e.g. 2-methoxycanthin-6-one).
Peristaltic activity was significantly increased in mice at an oral dosage of 1000 µg/kg aqueous extract of Quassia amara. Acute toxicity of orally administered aqueous extracts of Quassia amara has not been observed in standard tests with mice and rats. However, intraperitoneal administration did result in acute toxicity. Quassia tincture has been very effectively applied to control head lice, without side effects, thereby confirming this traditional application.
The crude methanol extract of the stem wood of Quassia amara caused a significant reduction in the weight of the testis, epididymis and seminal vesicle of rats, together with an increase of that of the anterior pituitary gland. Epididymal sperm counts, serum levels of testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) were significantly reduced when the rats were treated with the extract. Furthermore, the basal and LH-stimulated testosterone secretion of Leydig cells isolated from rats pretreated with the extract were inhibited. These changes seemed to be restored eight weeks after the withdrawal of extract treatment. Two compounds, quassin and 2-methoxycanthin-6-one were isolated after fractionation of the crude methanol extract. Quassin produced biological actions similar to those of the extract, whereas the effects of 2-methoxycanthin-6-one did not seem to differ from those of the controls. Thus, quassin appears to be the antifertility principle of Quassia amara.
Several quassinoids isolated from Quassia indica exhibited a variety of pharmacological effects. Samaderines B, E, X and Z were shown to exhibit significant growth-inhibitory activity against the cultured malarial parasite Plasmodium falciparum (a chloroquine-resistant K1 strain). Furthermore, samaderines B, C, E, X, Y, Z and indaquassin C and X were shown to exhibit in vitro cytotoxicity against KB-cells (IC₅₀ 0.04—1.00 µg/ml). Samaderines B, C and X as well as indaquassin X also exhibited inhibitory activity in the in vitro endothelial cell-neutrophil leukocyte adhesion assay, whereas samaderines B and X were found to exhibit significant anti-inflammatory activity too.
Aqueous extracts of Quassia amara have been successfully applied against cereal aphids and various pests in peach and apple, in both laboratory and field tests. Furthermore, quassin in aqueous extracts of Quassia amara effectively killed larvae of Culex quinquefasciatus, a known malaria vector, at a concentration of 6 ppm.

Several pharmacopoeias allow both the wood of Picrasma excelsa Planch. (from Jamaica) or the wood of Quassia amara (from Suriname) to be used as the simplex quassiae lignum. To differentiate between the 2 species, the wood of only Quassia amara might be known as 'quassiae lignum surinamense' or 'quassiae lignum verum'.

Shrubs or trees up to 25 m tall. Leaves spirally arranged, paripinnate or imparipinnate, or simple; petiolate; stipules absent; leaflets usually with pitted glands on the upper surface along the margin and especially at the apex. Inflorescence a simple or branched raceme, panicle or pseudo-umbel. Flowers 4—6-merous, unisexual, bisexual, or polygamous; petals imbricate or contorted in bud, longer than the calyx; stamens double the number of petals, hairy, adaxial scale with a shorter or longer free apex; disk present; carpels free or coherent, 4—6, style 1, but parts of carpels discernible. Fruit consisting of 1—6 drupaceous or woody parts, often compressed. Seedling with epigeal germination; cotyledons emergent, fleshy, hypocotyl elongated; leaves simple, the first two opposite, subsequent ones spirally arranged.

In a seedling trial in Malaysia, Quassia indica seed germinated in 57—181 days. Quassia indica flowers and fruits throughout the year.

Quassia is taken here in the broader concept to include Simaba and Simarouba. This broad concept has recently been disputed on grounds of molecular research.

The Malesian Quassia are confined to lowland forest.

Quassia can be grown from seed, cuttings and by means of air-layering. Partial shade is required for the early stages of growth.

Quassin can be produced from both callus and suspension cultures of Quassia amara stem and leaf explants. Quassin production in callus culture is promoted by adding naphthalene acetic acid or 2,4-D. Quassin yield in suspension culture in B5 medium can be as high as 0.25 mg/l per day.

Depending on site and light conditions, partial shading may be required over a longer period. Cut surfaces after harvesting of branches need proper tending to prevent infections, pest damage and to ensure proper healing.

Natural stands of Quassia exhibit little damage from diseases or pests.

Cutting of branches should be done so as to sustain health and vigour of plants to ensure future harvests.

Branches should be cut in smaller pieces to facilitate drying and prevent infections that would decrease the quality. Properly dried wood can be kept for a considerable time. The crude drug is usually marketed in the form of chips.

Neither Quassia amara, that is commonly cultivated, nor Quassia indica, with its large area of distribution, seem to be seriously threatened by genetic erosion.

The application of Quassia amara preparations in medicine is well known. Furthermore, in general quassinoids and canthin-6-ones display a variety of interesting pharmacological effects, which make them of potential use in the development of new templates for new drugs. Because of the growing resistance of malaria parasites to the well-known, and even newer, antimalarials currently in use, there is a continuous need to develop new compounds to control this almost global infectious disease. The quassinoids and the canthin-6-one alkaloids might also have good potential for the development of a cytostatic drug to treat various cancers.

Garcia-Gonzalez, M., Gonzalez-Camacho, S.M. & Pazos-Sanou, L., 1997. Pharmacologic activity of Quassia amara (Simarubaceae) aqueous wood extract on albino rats and mice. Revista de Biologia Tropical 44/45: 47—50. (in Spanish)
Jensen, O., Nielsen, A.O. & Bjerregaard, P., 1978. Pediculosis capitis treated with quassia tincture. Acta Dermato Venereologica 58(6): 557—559.
Kitagawa, I., Mahmud, T., Yokota, K.I., Nakagawa, S., Mayumi, T., Kobayashi, M. & Shibuya, H., 1996. Indonesian medicinal plants. XVII. Characterization of quassinoids from the stems of Quassia indica. Chemical and Pharmaceutical Bulletin (Tokyo) 44(11): 2009—2014.
Njar, V.C.O., Alao, T.O., Okogun, J.L., Raji, Y., Bolarinwa, A.F. & Nduka, E.U., 1995. Antifertility activity of Quassia amara: quassin inhibits the steroidogenesis in rat Leydig cells in vitro. Planta Medica 61(2): 180—182.
Nooteboom, H.P., 1962. Generic delimitation in Simaroubaceae tribus Simaroubeae and a conspectus of the genus Quassia L. Blumea 11(2): 509—528.
Raji, Y. & Bolarinwa, A.F., 1997. Antifertility activity of Quassia amara in male rats: in vivo study. Life Sciences 61(11): 1067—1074.

H.C. Ong

Quassia amara
Quassia indica

Ong, H.C., 2001. Quassia L.. In: van Valkenburg, J.L.C.H. and Bunyapraphatsara, N. (Editors): Plant Resources of South-East Asia No 12(2): Medicinal and poisonous plants 2. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea

The following species in this genus are important in this commodity group and are treated separatedly in this database:
Quassia amara
Quassia indica