Russian researchers from Novosibirsk have found out how to make some pharmaceutical agents less toxic without losing in efficiency and healing properties. The process, which does all abovementioned things, is called “clathration” – formation of a complex of a drug with natural polysaccharides.

Researchers from Novosibirsk Institute of Organic Chemistry have studied clathrating properties of a natural polysaccharide arabinogalactan, extracted from larch tree.

Arabinogalactan is a dry powder with weak pine odour and sweetish taste, which is very soluble in water. This natural polymer is widely used as a probiotic agent – eating arabinogalactan is believed to have a positive effect on gut microflora. Arabinogalactan promotes bowel movement, stabilizes cell membranes and stimulates immune system. Pharmaceutical industry uses this polymer as a binding agent for making pills.

As for United States of America, arabinogalactan is commercially produced in this country from wood of western larch (Larix occidentalis), which grows in northwest territories of North America. This polysaccharide can also be found in our country – in wood of Siberian endemic tree species: Siberian larch (Larix sibirica) and Dahurian larch (Larix gmelinii), which contain not less of 10% of arabinogalactan on dry weight basis.

Russian researchers have revealed that arabinogalactan from Siberian trees actively formed complexes with some pharmaceutical agents, for instance, with anti-inflammatory agents or with psychoactive ones. This property of the natural polymer can be used for clathration of these drugs in order to extend their lifetime in patient’s vasculature and to reduce a dosage, required for treatment. Most recent studies of the researchers are dedicated to effects of arabinogalactan on nifedipine, a drug, mainly used as an antihypertensive agent and known to have a long list of undesired side effects.

Tests of arabinogalactan effects were performed on laboratory animals. Hypertensive rats received injections with complexes, containing different ratios of nifedipine and the polysaccharide (1:4, 1:8 and 1:16) and various concentrations of a treating agent. Experiments have showed that the effect of arabinogalactan depended on the ratio between the treating agent and the polymer; however, any tested combinations of mentioned two substances had stronger and more stable effect, than nifedipine itself. Arabinogalactan is known to have no effect on arterial blood pressure. The researchers have demonstrated that clatration of a pharmaceutical agent allowed ten times reduction of its dose without losing any efficiency. Moreover, one of the complexes with nifedipine appeared to have significant antiarrhythmic activity, which surprised researchers, because pure nifedipine in the same concentration had zero effect on arrhythmia.

More studies are required to test the power of arabinogalactan complexes with other pharmaceutical, however, positive start has been given.