Phytomedicine, Vol. 6(3), pp. 181-185 Urban & Fischer Verlag 1999http://www.urbanfischer.de/journals/phytomed Phytomedicine

Salvadora persica L.: hypolipidemic activity onexperimental hypercholesterolemia in ratE. M. Galati, M. T. Monforte, A. M. Forestieri, N. Miceli, A. Bade, and A. TrovatoPharmaco-Biological Department, School of Pharmacy, Messina, Italy

Summary

Stems of Salvadora persica are widely used as tooth cleaning sticks in Arabic countries and decoctionsshow hypocholesterolemic properties.

The effects of prolongcd administration of a lyophilized stem decoction of Salvadora persica wereevaluated in diet-induced rat hypercholesterolemia. The preparation was administered for 15 and 30days (by gavage at a dose of 500 mg/kg in an aqueous vehicle in a volume of 0.5 ml/100 g b.w.). Choles-terol, HDL, LDL and triglyceride plasma levels were assayed. The results showed that the S. persica de-coction significantly lowered cholesterol and LDL plasma levels in rats, proving to be more active at 30days of treatment. The systemic administration of Triton results in a rise in plasma cholesterol and tri-glyceride levels. The results obtained show that S. persica decoction was inactive at 18 hr after treatment,whereas at 27 hr, it was able to reduce cholesterol and LDL plasma levels. In all experiments HDL andtriglycerides were unchanged.

Key words: Salvadora persica L., hypocholesterolemic activity, cholesterol, HDL, LDL, triglycerides.

IntroductionSalvadora persica L. is a desert plant which grows fromnorth-western India to Africa.

Branches and roots of S. persica are widely used as atooth cleaning-stick (Abderahim and Jurner, 1983; At-tar, 1979), but various other uses of this plant havebeen reviewed (Watt, 1962).

There are many references in the literature on its usein traditional medicine. Salvadora persica is used forgonorrhoea, spleen disorders, boils, sores, gum diseaseand stomachache (Boulos, 1983; Ayensu, 1979; Kok-waro, 1976). The wood, boiled in oil, constitutes a lini-ment used against contusions (Bellakhdar, 1978). Thebark is used against bites of poisonous animals (Bou-quet, 1921). Leaves, roots, bark and flowers contain adiuretic oil (Ducros, 1930; Ezmirly, 1979).

The leaves are used for cough, asthma, scurvy, rheu-matism, as an antiinflammatory and antisyphilitic (Fa-roogi and Srivastava, 1968; Ezmirly, 1979; Boulos,1983).

In order to confirm some of the locally reported me-dicinal properties of S. persica, we investigated a stemdecoction of this species for a number of biological ef-fects. In previous works we observed that the decoctionof S. persica possessed significant protective actionagainst ethanol and stress-induced ulcers in rats (Gala-ti et al., 1998) and we confirmed the antiulcer activityof S. persica decoction by optical microscopy (Sanogoet al., 1998). Moreover, a stem decoction of S. persicashowed hypoglycemic effects, in normal rats an in-crease in plasma immunoreactive insulin (IRI) and in-creased oral-glucose tolerance (Trovato et al., 1998).

This plant contains trimethylamine (Farooqi and Sri-vastava, 1968), related to urea alkaloids (Ray et al.,1975; Robinson, 1983), sulphur (Cornu and Massot,1975), organic sulphur compounds (Daxenbichler,1991, Miller, 1973), ~-sitosterol (Awasthi and Mitra,1964; Ezmirly et al., 1979), ascorbic acid (Faroogi andSrivastava, 1968; Kapoor, 1990; Boulos, 1983; Etkin,

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182 E. M. Galati et al.

1981; Lewis and Elvin-Lewis, 1977; Oliver, 1960),small amounts of saponins (Von Kampf, 1975; Ezmirlyet al., 1979) and lignan glycosides (Kamel et al., 1992).

Literature data show that some components of S.persica such as ~-sitosterol and ascorbic acid, show hy-pocholesterolemic properties (Nagy et al., 1977; Mali-ni and Vanithakumari, 1990).

Therefore it seemed of interest to evaluate the effectsof prolonged administration of a lyophilized decoctionof S. persica on rats with diet-induced hypercholesterol-emIa.

In the present study the effects on triton-induced hy-percholesterolemia were also recorded. Cholesterol,HDL, LDL and triglyceride plasma levels were deter-mined.

Materials and methodsPlant materialThe stems of Salvadora persica L. were obtained fromArabic commercial sources. The identity of the plantwas confirmed by bibliographic data (Farooqui andSrivastava, 1968; Kapoor, 1990; Cronquist, 1981).Voucher specimens are deposited at the Pharmaco-Bio-logical Department at the University of Messina.

50 g of powdered stems of S. persica were boiled with500 ml distilled water for 30 min. After filtration, thedecoction was lyophilized. The quantity of lyophilizedpowder obtained from 100 g of drug was 9.6 g.

The lyophilized powder was administered, in themorning, by gavage, at doses of 500 mg/kg, dissolvedin aqueous vehicle, in a volume of 0.5 ml/l00 g of bodyweight.

The reproducibility of our experiments was guaran-teed by a repetition of the experiment with a second de-coction prepared independently from the first one andthe results were analogous.

AnimalsAdult male Wistar rats (180-200 g) were used in all ex-periments. They were maintained in standardized con-ditions (temperature 22 2C; humidity 60% 4%,natural lighting) and water was provided ad libitum.

The food intake and growth rates were monitoredduring the treatment. The rats were divided into 8groups of 10 animals each.

At the end of every treatment, the animals were fast-ed overnight. Blood was collected, in heparinizedtubes, from the carotid artery of rats under light die-thyl-ether anaesthesia; the plasma was immediatelycentrifuged and kept at -20C until assayed.

Total cholesterol (Allain et al., 1974), HDL (HighDensity Lipoproteins), LDL (Low Density Lipopro-teins) (Vikari, 1976; Izzo et al., 1981; Grillo et al.,

1981) and triglycerides (Wahlefeld, 1962) were assayedwith colorimetric and enzymatic methods (BoehringerMannheim Diagnostica).

Statistical analysisData are expressed as mean S.E, of 10 determina-tions. The results were statistically analyzed byStudent's t-test P < 0.05, versus control was taken assignificant.

Diet-induced hypercholesterolemia in ratThe animals of group I were kept on a standard diet (S.Morini, Mill rat GLP), whereas the other groups of an-imals were fed with a hypercholesterolemic diet (cho-lesteroI2%, sodium cholate 2%, vitamin mixture 2%,oligoelements 0.2 %, salt mixture 5.8 %, coconut oil20%, cellulose 4%, sucrose 44%, casein 5%, drakett-protein 15%) supplied by Altromin-Rieper (Bolzano-Italy).

Group II was given only the hypercholesterolemicdiet for 30 days (controls); group III, also fed with a hy-percholesterolemic diet for 30 days, received lyophyl-ized stem decoction of S. persica, from the 15th to 30thday, once a day. Blood was collected at the end of treat-ment (30th day).

In order to verify the eventual protection exercised bythe S. persica decoction against the insurgence of hy-percholesterolemia, another group of animals (IV) wastreated with lyophilized decoction simultaneously withthe hypercholesterolemic diet for 30 days. Blood sam-ples for assays were collected after 30 days of treat-ment.

Triton-induced hypercholesterolemia in ratThe experiments were carried out according to themethod reported by Moss and Dajai (1972).

The animals of the groups V, VI, VII and VIII, fastedfor 18 hours, were injected intraperitoneally with Tri-ton WR-1339 (Isooctylpoly-oxyethilenephenol; Tylox-apol, Sigma-Chemical Co., St. Luis, MO) (100 mg/kgdissolved in 0.9% NaCl solution).

Lyophilized stem decoction of S. persica (500 mg/kg)was administered by gavage to the animals of groupsVII and VIII just after the triton injection.

Blood samples were collected 18 and 27 hrs after tri-ton and S. persica decoction administration.

Results and conclusionThe results showed that S. persica decoction, under ourexperimental conditions, influenced lipid metabolism.

A hypercholesterolemic diet administered for 30 daysincreases serum cholesterol and triglyceride levels. The

Salvadora persica L.: hypolipidemic activity on experimental hypercholesterolemia in rat 183

cholesterol mgldl

trlglycerldes mg/dl

Standard dietHyperchol. diet

Hyperchol. diet +S. perslca 15 days

Hyperchol.dlet+S. perslca 30 days

DHDL mgldlDLDL mgldlo triglycerides mgldlI?J cholesterol mgldl

Fig. 1. Cholesterol, HDL, LDL,triglyceride plasma levels in ratwith diet-induced hypercholester-olemia, after 15 and 30 day-treat-ment with stem decoction of Sal-vadora persica L. (500 mg/kg).

Fig. 2. Cholesterol and LDL plasma levels in rat with triton-induced hypercholesterolemia at 27 hrs after administrationof stem decoction of Salvadora persica L. (500 mglkg).(M S.E.) " P < 0.05 compared to controls; Student's t-test.

The systemic administration of triton results in a risein plasma cholesterol and triglyceride levels (Moss andDajai, 1972). This hypercholesterolemia is biphasic. In-itially, there is a sharp increase in serum cholesterol lev-els (Phase I), and the hypercholesterolemia falls offwithin the next 24 hrs (Phase II).

The results obtained at 18 hr, show that S. persica de-coction was inactive in the anabolic phase (Phase I),whereas at 27 hr, it was able to reduce cholesterol andLDL plasma levels in the catabolic phase (Phase II)(Fig. 2). Therefore we hypothesize that S. persica de-coction enhances cholesterol excretion in the form ofbile acids or of other sterols.

standard diet

o triton S.persicadecoction 27 h

o triton 27h

LDL 27 hoursCHOLESTEROL

216192168144

:E 120~ 96

724824o

oral administration of S. persica decoction for 15 days,significantly reduced cholesterol and DL, respectivelyby 10% and 18%.

Treatment with S. persica decoction, administered si-multaneously with the hypercholesterolemic diet for 30days had more marked effects on cholesterol and LDL(23% and 38%).

In triton-induced hypercholesterolemia, after admin-istration of S. persica decoction, it has to be noted that,after 18 hr, cholesterol and triglyceride plasma levelsremained unchanged, but were lowered significantly,27 hr after administration. The percentage reduction ofcholesterol and LDL respectively was 30% and 51 %.

In all experiments HDL and triglyceride concentra-tions were unchanged.

In rats kept on a hypercholesterolemic diet, hyper-cholesterolemia is exogenous, thus endogenous choles-terol biosynthesis proceeds at a very low rate to com-pensate the high serum cholesterol levels introduced bythe diet.

Under these experimental conditions S. persica de-coction lowers cholesterol and LDL plasma levels inboth tests (15 and 30 days), proving to be more activeat 30 days of treatment. The results obtained clearlydemonstrate that the decoction has a significant hypo-cholesterolemic activity and provides a considerableprotection against insurgence of diet-induced hyper-cholesterolemia (Fig. 1). These effects of S. persica de-coction can be due to one or more mechanisms involv-ing inhibition of intestinal absorption of cholesterol,enhancement of cholesterol degradation and interfer-ence with lipoproteins (Moss and Dajai, 1972).

184 E. M. Galati et al.

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Fig. 3. Effect of daily oral administration of Salvadora persi-ca L. decoction on body weight in rat. (M S.E.) * P < 0.05compared to controls; Student's t-test.

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Chronic administration of S. persica decoction alsocaused a significant decrease in mean body weights ofrats, without reduction in food consumption (Fig. 3),and showed hypoglycemic activity (Trovato et al.,1997). Therefore we suggest that it might interfere withthe absorption processes from the lumen of the smallintestine.

The absence of a remarkable HOL increase and thepresence of a significative LOL decrease might be relat-ed to up-regulation of LOL hepatic receptors whichcatabolize LOL (Kovanen, 1981). It was also con-firmed by the effect of S. persica decoction on the cata-bolic phase of triton-induced hypercholesterolemia.

The active principles contained in S. persica probablyinterfere simultaneously with several biochemical path-ways. Therefore further work is needed to clarify themechanisms of these biological actions.

It is well known that LOL plays an important role inatherogenesis and that hypercholesterolemia is asso-ciated with a defect relating to the lack of the LDL re-ceptors. The decrease of cholesterol and LOL plasmalevels exercised by S. persica decoction, demonstrated apossible protection the insurgence of exogenous hyper-cholesterolemia and the harm this condition bringsabout. In conclusion, the use of this plant, widelyknown in Traditional Arabic Medicine, appears partic-ularly recommendable.

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AddressE. M. Galati, Pharmaco-Biological Department, Schoolof Pharmacy, Vill. SS. Annunziata, 98168 Messina, Italy