Agriculture Reference
In-Depth Information
Synonyms —
Embellia grossularia
Retz.,
Galenia asiatica
Burm.f.
Family —
Salvadoraceae
Common Names —
Toothbrush tree, Siwak, Miswak
African Names —
Arabic: shiwak; Masai: o, remit; Swahili: msuake, mswaki, musuake
Description —
Salvadora persica
is a small tree, usually with crooked stem and drooping
branches. The leaves are elliptic lanceolate, obtuse, cuneate, or with a rounded base. Flowers are
greenish yellow, borne in axillary and terminal lax, clustered toward the tip of the branches, with
panicles 5-12 cm long; the corolla is twice as long as the calyx. It produces one-seeded, globose
drupes, 3 mm in diameter and red when ripe.
166
It has been observed that the large amount of intra-
axillary phloem and the widely spaced, thick-walled fibers in the pericycle of the root allow the
spongy wood to be easily crushed by the teeth and softened, if dry, with water.
227
The fiber-like
quality of the wood is also aided by the numerous thick-walled vessels and fibers found in the xylem.
Habitat and Distribution —
The plant grows in secondary forests and semisavanna. It is found
in North Africa and parts of East and Central Africa.
Ethnomedicinal Uses —
Salvadora persica
has been known as the toothbrush tree for several
centuries.
923
It is used widely in Africa, Arabia, and parts of India for cleaning the teeth.
Salvadora
was mentioned in the Arabian ancient script the Muwashsha (AD 900) as a chewing stick or shiwak.
The root bark is considered a remedy for ancyclostomiasis by the Nyamwezi. The Massai employ
the paste of the powdered root in a decoction for venereal diseases and for catarrh. In East and
Central Africa, the plant is used for oral hygiene and as an ascarifuge.
Constituents —
The plant is rich in chlorine, resin, and trimethylamine and has a high ash
value of 27.06%. It also contains sulfur, silica, tannins, saponins, and vitamin C.
924
The oil cake
from the seeds contains nitrogen (4.8%), potash (2.8%), and phosphoric anhydride (1.05%).
170
One of
the major constituents of siwak is benzyl isothiocyanate (BITC), isolated from the roots.
924
Pharmacological Studies —
Salvadora
has been incorporated into many commercial tooth-
pastes. It possesses antiplaque activity.
925
BITC isolated from
Salvadora
has virucidal activity
against HSV, inhibits the growth and acid production of
Streptococcus mutans
, and is fungistatic
to
Candida albicans
.
In vitro
studies of shiwak extracts have also demonstrated some antibacte-
rial activity against certain bacterial species implicated in periodontal disease and dental caries.
926
Clinical studies on saliva showed that using shiwak sticks or rinsing with aqueous shiwak extract
has an immediate inhibitory effect on salivary bacteria.
927,928
Among chronic or habitual users,
clinical studies have shown some positive effects of siwak on their dental health.
929,930
In a double-blind, randomized, controlled trial, 68 patients with gingivitis were randomly
assigned to miswak group and were instructed to use only issued miswak for oral hygiene during
the 3-week experimental period. Registration of plaque, gingival inflammation, and plaque samples
were taken at baseline and on completion of the study. Plaque samples were analyzed by a DNA-
DNA hybridization technique. Miswak significantly reduced dental plaque (
p
= 0.007) and the
composition of subgingival microbiota. Miswak showed an overall effect on dental plaque and gin-
gival inflammation scores. It was suggested that miswak can be used as a dental hygiene method in
conjunction with interproximal cleaning aides.
931
Extracts of the leaves are used in the treatment of scurvy for rheumatism and as a decoction in
asthma and for a cough.
134
Oil obtained from the flower is a stimulant and laxative and has been
used as a carminative, anthelmintic, analgesic, and antimicrobial agent.
166
The effects of prolonged
administration of a lyophilized stem decoction of
Salvadora persica
have been evaluated in diet-
induced rat hypercholesterolemia. The preparation was administered for 15 and 30 days (by gavage
at a dose of 500 mg/kg in an aqueous vehicle in a volume of 0.5 ml/100 g body weight). Cholesterol,
HDL, LDL, and triglyceride plasma levels were assayed. The results showed that the
S. persica
decoction significantly lowered cholesterol and LDL plasma levels in rats, proving to be more active
at 30 days of treatment. The systemic administration of Triton X-100 (surfactant) resulted in a rise in
plasma cholesterol and triglyceride levels. The results showed that
S. persica
decoction was inactive
