Zinopin--the rationale for its use as a food supplement in Traveller's thrombosis and motion sickness.

Venous thrombo-embolism (VTE) has been associated with periods of prolonged immobility during air, sea and road travel. Motion sickness (MS) has also been reported during both long and short journeys. Current prophylactic therapies for both these indications are generally associated with side effects. Physiological profiles of Pycnogenol and Standardized Ginger Root Extract (SGRE) representing active constituents of Zinopin have been described and reviewed in relation to their activities involved in the patho-physiology of VTE (Traveller's Sickness) and MS and their safe use as food supplement, in traveller's thrombosis and motion sickness. The pathophysiology of VTE and MS is discussed in light of epidemiological data and risk factors associated with these conditions. Rationale of development of Zinopin and its mechanism of action are discussed based on physiological synergy of Pycnogenol and SGRE. Conclusions are made in light of preliminary clinical findings obtained in an open controlled clinical trial. Further clinical study on Zinopin on these lines is suggested.

The effect of Pycnogenol on fluoride induced rat kidney lysosomal damage in vitro.

Pycnogenol (PYC) is a procyanidin-rich extract of the bark of French maritime pine (Pinus pinaster) with a potent ability to scavenge free radicals. Lysosome-rich fractions from rat renal cortices were incubated with varying amounts of PYC and challenged with noxious doses of fl uoride. Controls were also included. The release of N-acetyl-beta-D-glucosaminidase (NAG) isozymes in the supernatant was estimated by spectrophotometric methods. The protein content of the renal cortex was also determined. Our results show that fluoride in unhealthy doses can cause a concentration dependent release of N-acetyl-beta-D-glucosaminidase (NAG) isozymes from the renal lysosomes. This may be related to its known ability to initiate free radical formation or direct damaging effects on the lysosomal membrane. As a blend of bio flavonoids pycnogenol has a potent ability to scavenge free radicals. In our study PYC was effective in preventing fluoride induced release of NAG isozymes from the renal lysosomes.

Pycnogenol prevents haemolytic injury in G6PD deficient human erythrocytes.

Glucose6 phosphate dehydrogenase (G6PD) deficiency is the most common X-linked disorder of human erythrocytes where cells have inadequate capacity to destroy peroxides and high susceptibility towards haemolytic changes. Pycnogenol is a proprietary dry extract of the French Maritime pine (Pinus pinaster) bark with high ability to scavenge free radicals. In the present study we have investigated if Pycnogenol can protect G6PD deficient erythrocytes against haemolytic cell damage. Venous blood samples were obtained from six subject of Mediterranean origin with known G6PD deficiency which was also confirmed with standard techniques. Erythrocyte haemolysis in the presence and absence of Pycnogenol was induced either with tert-butylhydroperoxide (t-BHP) or quinine and the haemoglobin release in the supernatant was determined by recording the optical density at 540 nm in a Shimadzu spectrophotometer. Our results have shown that Pycnogenol has protective action against a Xenobiotic chemical induced haemolysis in G6PD deficient human erythrocytes.

Pycnogenol inhibits the release of histamine from mast cells.

Oxygen derived free radicals are now increasingly regarded as a primary force of tissue destruction and also have the ability to release histamine from mast cells. Pycnogenol is an extract of the bark of French maritime pine (Pinus pinaster) containing bioflavonoids with a potent ability to scavenge free radicals. Therefore Pycnogenol was investigated for inhibition of histamine release from rat peritoneal mast cells. In addition, its effects were compared with sodium cromoglycate, a known inhibitor of histamine release from the mast cell. Rat peritoneal mast cells were isolated and purified by differential centrifugation and cells pooled from 3-4 animals were suspended at approximately 10(6) cells/mL buffered salt solution. Histamine release was induced by compound 48/80 or the calcium ionophore A-23187 and estimated from supernatant following extraction and by fluorimetric methods. Pycnogenol produced a concentration dependent inhibition of histamine release induced by the two secretagogues. Its inhibitory effect on mast cell histamine release was favourably comparable to sodium cromoglycate.

Cytoprotective effects of Bencianol on porcine vascular endothelial cells in vitro.

Endothelial cells of porcine thoracic aorta were chosen as in vitro model to study the reaction of endothelial cells to injury induced by carbon tetrachloride (CCl4 0.2 microliter/ml). Lactate dehydrogenase (LDH) was used as the biochemical marker of cell injury. The changes in the morphology of the surface endothelial cells were observed by scanning electron microscopy. In addition, cell survival rate after replating cultures was evaluated. The pretreatment with Bencianol (10(-10) M-10(-7) M) produced cytoprotective effects against CCl4 induced cell injury on the above three parameters.

Effect of dose schedule of vitamin E and hydroxethylruticide on intestinal toxicity induced by adriamycin.

CDF1 mice receiving Adriamycin, 12 mg/kg IP develop a toxic GI mucositis. The mean survival in CDF1 mice after Adriamycin injection was found to be 6.5 +/- 2.0 weeks and could be increased by alcohol or acetate Vitamin E pretreatment (with 2 g/kg qDx7d) to 22.06 +/- 12.3 weeks or by treatment with Venoruton after Adriamycin (qDx7 with 1.5 g/kg) to 23.7 +/- 12.7 weeks. Other schedules were ineffective or harmful. The ability of Venoruton to enhance survival when given after Adriamycin encouraged us to proceed to tumor bearing mice. The maximum survival with CDF1 mice bearing 5 X 10(6) L1210 cells was 1 +/- 0.2 week which could be increased to 2.17 +/- 0.8 weeks with optimal dose Adriamycin (10 mg/kg). Optimum survival with Venoruton and a single dose of Adriamycin was 2.45 +/- 0.91 weeks with Venoruton, 1.5 g, qd X 14, and 12 mg/kg Adriamycin. Treatment of L1210 bearing mice with Adriamycin, 10 mg/kg on days 1 and 8, yielded a survival of 2.23 +/- 0.7 weeks. An equitoxic regimen of Adriamycin, 11 mg/kg on days 1 and 9, plus Venoruton, 1.5 g, qd X 14, increased survival 30% to 3.08 +/- 2.9 weeks. Venoruton is a promising agent to increase the therapeutic index of Adriamycin.

Anti-spasmogenic effects of bencianol (ZY15051) on human cerebral arteries in vitro.

Experiments were performed to assess the ability of bencianol (ZY15051) to reverse contractions of human basilar arteries in vitro that were induced by a wide range of substances implicated in the aetiology of migraine and cerebral arterial spasm. Bencianol caused a dose-related (1-100 micrograms ml-1) reversal of contractions induced by 5-hydroxytryptamine, noradrenaline, angiotensin II, prostaglandin F2 alpha, and U-46619 (a thromboxane-A2 mimetic). Bencianol was more effective against contractions induced by EC50 compared to maximal concentrations of each agent, and was least effective against the thromboxane-A2 mimetic, U-46619. In addition, contractions induced by thromboxane-A2-like substances generated from guinea-pig lungs were also reversed by bencianol but only at the highest concentration used (100 micrograms ml-1). The relevance of this action of bencianol to migraine and cerebral arterial spasm is discussed.

Role of calcium in the histamine release induced by D-galactosamine from rat mast cells.

Rat peritoneal mast cells were isolated and purified by differential centrifugation in Ficoll. Cells pooled from three to four rats were suspended at approximately 10(6) cells/ml in a buffered salt solution and incubated for 1 h at 37 degrees C in 300 microliter volumes in the absence or presence (9 X 10(-4) M) of calcium chloride. Addition of D-galactosamine hydrochloride (DGM; 2.8 X 10(-4)M) caused (in addition to basal release) a mean +/- SEM percent histamine release of 15.7 +/- 5.2 in the presence of Ca++ and 19 +/- 4.9 in the absence of Ca++ (p greater than 0.05). It is suggested that D-galactosamine does not require extracellular Ca++ for the release of histamine from the rat mast cell.

Protective effects of O-(beta-hydroxyethyl)-rutosides (HR) against adriamycin-induced toxicity in rats.

Adriamycin (Adriablastine), administered weekly at the dose of 5 mg/kg i.p. for 3 weeks in rats, produced a general decrease of vitality associated with a decrease of body weight, hypothermia, decreases of stroke volume and cardiac output. Hematocrit was decreased. Renal blood flow decreased whereas pulmonary blood flow increased. Mean blood pressure and heart rate remained unaffected. Biochemical evaluations revealed a decrease of blood urea and serum creatinine, which might be related to decreased food intake and protein metabolism. Morphological changes in the heart tissue could not be appreciated. Venoruton (HR), administered at the dose of 300 mg/kg p.o. daily for 28 days (5 days before and 23 days after the first injection of adriamycin), improved adriamycin-induced clinical signs and symptoms (loss of body weight, hypothermia and decreased general vitality). It tended to increase cardiac output and stroke volume.

Histidine decarboxylase inhibition: a novel approach towards the development of an effective and safe gastric anti-ulcer drug.

The involvement of histamine in mediating gastric function under normal and pathological conditions has been largely established. The relationship between gastric acid production and peptic ulcer diathesis is also well known. Recently, endogenous histamine formation and its release from mast cells has been implicated in the pathogenesis of human and experimental gastric ulcers produced by restraint and pyloric ligation. It has also been implicated in the gastric mucosal damage produced by drugs like aspirin, phenylbutazone and reserpine. These observations suggest that histidine decarboxylase inhibitors may be useful in the prevention of such lesions. Our studies on the evaluation of some histidine decarboxylase inhibitors show that these compounds have a promising potential for developing an effective and safe anti-ulcer drug. This mini-review incorporates the results of our studies which have been adequately supported by other studies as well.

Hemodynamic studies in acute venous stasis edema in rats.

An increase in venous pressure in the rat tail is known to result in acute edema. Acute venous stasis edema of the rat tail was induced by applying a force-controlled banding of standard tension (200 g) proximally for a period of 6-12 h. The hemodynamic changes of acute venous stasis edema were evaluated using non-invasive plethysmography, fluorescence angiography, computer thermography and invasive radioactive microsphere techniques. It is shown here that reduction of tail circulation to 40% of the control value is followed by prolonged vascular disorder characterized by genesis of reversible edema, increased total blood flow to the tail and decreased local cutaneous blood flow, without affecting the general hemodynamics. The cutaneous circulation (decreased blood flow) seems to be principally involved in the edemogenic response, whereas the deeper vessels (hyperemia) may or may not play a determinant role in acute experimental venous stasis edema in rats.

Hemodynamic, biochemical and morphological changes in the dextran and D-galactosamine-induced edemas in rats.

Dextran (600 mg/kg i.p.) and D-galactosamine (300 mg/kg s.c.)-induced edemas in the rat have been evaluated and compared on the basis of hemodynamic, biochemical and morphological investigations. The genesis of the edema induced by dextran was quicker (1-3 hr) than that induced by D-galactosamine. The edema index at the levels of the paws was higher in the dextran (10.5 +/- 0.6) than in the D-galactosamine (5.1 +/- 0.4)-induced edema. Furthermore, the dextran-induced edema was associated with marked hypotension and a decrease in the plasma protein levels. Bradycardia, decrease in the cardiac output and the coronary blood flow were observed in both the edemas. Blood flows to the brain, kidneys, lungs, spleen and paws were decreased only in the dextran-induced edema. It was interesting to note that the percentage distribution of the cardiac output in the paws was decreased in the dextran-induced edema only. PGE2 levels were increased, whereas the histamine levels were decreased in the paw-skin in both the edemas. These changes were relatively more marked in the dextran edema. The levels of PGF2 alpha remained unchanged. The above findings have been further supported by our morphological data where relatively more degranulation of the mast cells and that too at a shorter period, was observed in the dextran-induced edema. Different mechanisms for the genesis of these two kinds of edemas have been suggested.

Pharmacodynamic studies with flunarizine, a calcium influx blocker.

Flunarizine, a difluoro derivative of cinnarizine, has been used to study its antivasoconstrictor effects on isolated perfused rat mesentery. The vasoconstrictor responses induced by sequential intra-arterial injections of phenylephrine (PhE) and norepinephrine (NE), were measured as an increase in the perfusion pressure (mm Hg). Flunarizine was administered either by i.v. route in a dose of 3 mg/kg, 15-20 min before the isolation of the mesentery or it was added to the perfusing medium, in concentrations ranging from 100 pg to 1 microgram/ml (PhE experiments) and from 1 ng to 1 microgram/ml (NE experiments). Intravenous administration of flunarizine significantly decreased the vascular reactivity of rat mesentery to PhE and NE at all dose levels. Continuous perfusion of flunarizine attenuated the vasoconstrictor responses induced by PhE and NE. Flunarizine was further studied for its hemodynamic effects in anaesthetized rats using the radioactive microspheres technique. Flunarizine (5 mg/kg i.p.) was administered 60 min prior to the determination of hemodynamic parameters. It was found not to affect general hemodynamics (mean blood pressure, heart rate, cardiac output and hematocrit). However, it produced a significant decrease of renal and splenic blood flows. The changes in blood flows were associated with similar changes in the percentage distribution of cardiac output to these organs, thus indicating that local regulatory mechanisms were influenced by flunarizine. It appears that flunarizine has preferential effects on the different vasculatures in vivo, whereas it produces nonspecific inhibition of exogenous PhE and NE in the rat mesentery in vitro.

Effects of leukotriene C4 and prostaglandin E2 on the rat mesentery in vitro and in vivo.

Leukotriene C4 (LTC4) and Prostaglandin E2 (PGE2) have been studied for their effects on the rat mesentery in vitro and in vivo. Their effects on the norepinephrine (NE) induced vasoconstrictions in the above vascular bed have also been investigated. LTC4 (10(-10)M) and PGE2 (2.8 X 10(-7)M) produced no direct effects on the perfusion pressure in the isolated perfused rat mesentery. However, LTC4 (10(-10)M) produced constriction of the arterioles in vivo. PGE2 (2.8 X 10(-7)M) did not produce any direct effect on the microcirculation. Indomethacin, when superfused for 10 min. in a concentration of 7 X 10(-5)M, produced significant arteriolar constriction; this effect was reversed when PGE2 was added to the superfusing media containing indomethacin. LTC4, perfused in a concentration of 10(-10)M, produced a time - dependent inhibitory effect on NE induced vasoconstrictions in vitro whereas PGE2 perfusions (2.8 X 10(-7)M) potentiated the NE responses. This potentiating effect of PGE2 was inhibited by indomethacin. In contrast, the topical application of PGE2 in vivo attenuated NE responses of the mesenteric arterioles.

The local edemogenic effects of leukotriene C4 and prostaglandin E2 in rats.

Leukotriene C4 (LTC4) and prostaglandin E2 (PGE2) have been studied for their effects on vascular permeability in rats. LTC4 and/or PGE2 were dissolved in 0.3% ethanol and were administered subcutaneously (0.1 m1) in the plantar surface of one of the hind paws of different series of rats. The changes in vascular permeability were measured by the radioactive marker (HSA.I125) method. LTC4 administered in dose of 2 X 10(-8) M produced marked increase (77 and 133%) in the vascular permeability (local edemogenic effect). PGE2 administered in a dose of 10(-6) M also produced significant increase (38 and 40%) in the vascular permeability. However, PGE2 in the same dose either administered along with LTC4 or administered at 30 minutes after the injection of LTC4 (2 X 10(-8) M) did not have any potentiating effect on the edemogenic response of LTC4.

Pharmacological and hemodynamic studies on flunarizine.

Systemic administration of flunarizine (3 mg/kg i.v.) to rats decreased the vascular reactivity of their mesenteries to phenylephrine (PhE) and norepinephrine (NE). Intra-arterial perfusion of flunarizine (100 pg to 1 microgram/ml) produced dose dependent attenuation of the vasoconstrictor responses induced by PhE and Ne in the isolated perfused rat mesentery. Flunarizine (5 mg/kg i.p.) did not significantly affect general hemodynamics (i.e. mean blood pressure, heart rate, cardiac output and hematocrits) in anaesthetized rats. However, it produced significant decreases in the blood flows to the kidneys and the spleen associated with similar changes in the percentage distribution of the cardiac output to these organs. These studies indicate that in rats, flunarizine produced preferential effects in different vascular beds.

Modulatory effects of substance P on norepinephrine induced vasoconstrictor responses in the rat mesentery.

1. The role of substance P (SP) in adrenergic transmission has been studied in the isolated perfused rat mesentery. 2. Intra-arterial perfusion of SP (4 x 10(-9) to 4 x 10(-7)M) produced a dose dependent potentiation of norepinephrine (NE) induced vasoconstrictor responses and a shift of the log dose--response curve to the left. 3. Saralasin, a specific antagonist of angiotensin II (ang. II) when perfused at a concentration of 3 x 10(-9)M did not change the NE responses as such. However, the potentiating effect of SP could not be demonstrated in the presence of saralasin. 4. Indomethacin, a prostaglandin (PG) synthetase inhibitor, when perfused at a concentration of 2.8 x 10(-6)M, markedly attenuated the vascular responses to NE, which could not be normalized by the addition of SP. 5. It appears that SP's potentiating effect on NE responses in the perfused rat mesentery simulates ang. II and not prostaglandins. A direct non-specific post synaptic sensitizing effect of SP on vascular smooth muscle cell, for its potentiating property, cannot be ruled out.