Amaranthus spinosus

Synonyms
Galliaria spitosa (L.) Nieuwl., Amaranthus spinosus var. viridicaulis Hassk., Amaranthus spinosus var. rubricaulis Hassk., Amaranthus spinosus var. pygmaeus Hassk., Amaranthus spinosus var. purpurascens Moq., Amaranthus spinosus f. inermis Lauterb. & K.Schum., Amaranthus spinosus var. indehiscens Thell., Amaranthus spinosus var. circumscissus Thell., Amaranthus spinosus var. basiscissus Thell.

Common name
Bayam duri, bayam hutan, spiny amaranth, prickly amaranth, spiny pigweed

Morphology

Leaves
Arranged alternate, simple and entire, ovate-lance-shaped to rhomboid, measuring 3.5-11 cm x 1-4.5 cm, acute and slightly decurrent at base, obtuse, rounded or slightly retuse and often short mucronate at apex, hairless or slightly hairy on veins when young. The petiole is rather long and approximately as long as leaf blade. Stipules are absent.

Inflorescence
Consists of dense clusters. The lower ones are axillary while the higher ones are often collected in an axillary and terminal spike which is often branched in its lower part. The axillary clusters are usually armed with (1-)2(-3) very sharp spines up to 2 cm long. The flowers are solitary in the axil of a bract, subtended by 2 bracteoles, with scarious bracts and bracteoles, mucronate from a broad base, shorter or as long as the perianth and unisexual. The male flowers are usually arranged in a terminal spike above the base of the inflorescence and it is green. There are 5 tepals or often 3 in male flowers, free, subequal, ovate-oblong to oblong-spatulate, measure up to 2.5 mm long, very convex, membranous, with transparent margins and green or purple median band. There are 5 stamens and they are about as long as tepals. The ovary is superior, oblong, 1-celled, with 2-3 styles and ultimately recurved.

Fruit
An oblong utricle with persisting styles, circumscissile a little below the middle or indehiscent and 1-seeded. 

Seed
About 1 mm in diametre, shiny black or brownish-black with thin margin. Seedling is with epigeal germination. Cotyledons are leafy and hairless while apex is rounded to slightly acute. The hypocotyl is up to 12 mm long while epicotyl is absent.

Chemical compound
A. spinosus has been reported to contain 7-p-coumaroyl apigenin 4-O-β-D-glucopyranoside, coumaroyl flavone glycoside (such as spinoside, xylofuranosyl uracil, β-D-ribofuranosyl adenine, β-sitosterol glucoside, hydroxycinnamates, quercetin and kaempferol glycosides), betalains, betaxanthin, betacyanin, amaranthine and isoamaranthine, gomphrenin, betanin, β-sitosterol, stigmasterol, linoleic acid, 0.15% rutin and β-carotene.

Plant part used
Root, leaf and tender shoot.

Medicinal uses

• The dichloromethane extract of A. spinosus (2mg/mL) was moderately inhibitory to Blastocystis hominis, a common human protozoan. The reference anti-protozoan agent, metronidazole (40 µg/mL) killed 97% of the protozoan and inhibited all protozoan samples at concentrations of 1.25-20 µg/mL.
• Methanol extract of A. spinosus extract (25-100 mg/kg) showed anti-inflammatory activity by significantly inhibited carrageenan-induced rat paw edema and produced significant inhibition of acetic acid-induced increase in vascular permeability indicating that the extract has anti-inflammatory activity.
• The extract (25-100 mg/kg) elicited a significant reduction in castor oil-induced diarrhea.
• The aqueous extract of A. spinosus bark obtained from mature stems was screened for antimalarial properties in mice inoculated with erythrocytes parasitized with Plasmodium berghei berghei.
  

List of country
Southeast Asia, South America and Central America

Nur Athirah Roshaizi

Nur Athirah Roshaizi

English