Anti-hyperglycaemic effect and nutritional properties of an aqueous extract of Larrea divaricata Cav. (jarilla) in streptozotocin-induced diabetes in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Larrea divaricata Cav. (Zygophyllaceae) (jarilla) is a native plant of South America widely distributed across Argentina and used in popular medicine to treat diabetes and hypercholesterolemia by the Diaguita-Calchaquí, Amaichas, and Quilmes indigenous communities and by non-indigenous population (criollos) of Calamuchita, in the province of Córdoba, Argentina. L. divaricata has also proved to have anti-inflammatory properties. However, the antidiabetic effects and the nutritional properties of the aqueous extract (AE) of this plant remain to be scientifically determined.

AIM OF THE STUDY

The aim of the present work was to evaluate the capacity of an aqueous extract of L. divaricata (AE) and its main compound nordihydroguaiaretic acid (NDGA) to modulate the glucose, cholesterol, triglycerides and oxidative stress levels in STZ-induced diabetes in mice. The general objective of the present work was to search for extracts that can be used as adjuvant therapy in for diabetes. The suitability of the extract to be used as a dietary supplement was also assessed by determining the proximate amount of fibre, lipids, proteins, and minerals.

MATERIALS AND METHODS

Diabetes was induced in mice by administration of streptozotocin (STZ). AE and NDGA were administered by the oral route. The animals' glycaemia was periodically monitored in blood samples obtained from the tail vein. The glucose dehydrogenase method was used. The effect of the AE on cholesterol, triglycerides, oxidative stress, lipid peroxidation and reduced glutathione (GSH) levels were determined in plasma samples by spectrophotometric assays.

RESULTS

In STZ-treated mice, AE significantly decreased glucose (33%, ****p < 0.0001) and cholesterol levels (32%, **p < 0.01). AE and NDGA decreased lipid peroxidation (30% and 38%, respectively, ****p < 0.0001), and increased GSH levels (20%, **p < 0.01). The effects of AE on glucose and lipid levels could not be ascribed to NDGA; however, this compound was involved in the extract antioxidant effects. The overall effects of AE were probably related to its antioxidant activity and to the anti-hyperglycaemic effect mainly mediated by flavonoids, fibre (carbohydrates) and mineral elements such as potassium, calcium, magnesium, and zinc. The AE protein content also confers the extract nutritional properties.

CONCLUSIONS

These results support the hypothesis that AE could be used as a therapeutic adjuvant or as a nutritional supplement to control glucose levels and lipid metabolism in metabolic syndrome-associated diseases. Moreover, these results scientifically reinforce the popular use of the plant.

Plants utilized as medicines by residents of Quilombo da Fazenda, Núcleo Picinguaba, Ubatuba, São Paulo, Brazil: A participatory survey

ETHNOPHARMACOLOGICAL RELEVANCE

Participatory research can help to broaden the understanding of medical systems and beliefs of traditional communities. An ethnopharmacological survey in collaboration with local people focused on plants used in quilombos located in Southeast Region in Brazil identified cultural factors that influence plant and recipe choice.

AIM OF THE STUDY

To investigate the factors related to the therapeutic efficiency of medicinal plants from the perspective of Quilombo da Fazenda residents.

MATERIALS AND METHODS

University researchers collaborated with community residents for both aims and methods of the study. The local partners were trained in the gathering of ethnopharmacological data and then selected and interviewed the residents considered experts on the use of medicinal plants. Data on the use of each species were supported by voucher specimens collected by the local partners and university researchers. Participant observations and field diaries by the university researchers supplemented the data.

RESULTS

Eight interviewees mentioned 92 medicinal species with 60 therapeutic uses, applied in 208 recipes or remedies. Asteraceae (13 species), Lamiaceae (5) and Urticaceae (5) contributed most medicinal plant species. Of the 12 etic categories of use, the circulatory system category had the highest number of plants mentioned. Decoction was the most commonly used preparation method (66.8%), and most remedies were administered orally (76.4%). Eighty-six recipes included more than one plant species and/or the addition of other components, such as sugar, salt or animal products. Several cultural factors influence medicinal plant use. Popular beliefs on the quality of blood or the humoral properties of plants and illnesses, characteristics of the plants and other factors determine which plant is used and why.

CONCLUSIONS

The participatory method identified a large number of factors that influence medicinal plant use: the patient's blood type; the condition of the plant and the disease (hot-cold system); the route of administration and dosage; the preventive uses of the plants; and the influence of other factors, such as the sun, the moon and dew. The participatory approach is useful for gaining insight on the decision processes of medicinal plant use in traditional societies, and also for those communities wanting to document their knowledge with or without the participation of the academy.

Jodina rhombifolia leaves lyophilized aqueous extract decreases ethanol intake and preference in adolescent male Wistar rats

The leaves of Jodina rhombifolia (Hook. & Arn.) Reissek (Santalaceae) are utilized as anti-alcoholic in Argentine folk medicine. This study was designed to investigate the anti-alcohol properties in adolescent male Wistar rats (postnatal day 29; 83-105 g of weight). We utilized the "self-administration model", which ethanol was offered in the standard home-cage through two-bottle free-choice regimen between an ethanolic solution (20% in tap water, v/v) and tap water with unlimited access for 24h per day for 10 consecutive days. The results obtained show that repeated administration of J. rhombifolia lyophilized extract, markedly reduced ethanol voluntary intake on dose dependent bases. The magnitude in reduction of daily ethanol intake was approximately 29%, 44% and 68%, for the rat groups treated with 62.5, 125 and 250 mg/kg of extract, respectively. Ethanol preference (proportion of ethanol intake versus total fluid intake) was significantly reduced: 21.37% ± 0.79 (0 mg/kg); 15.83% ± 0.93 (62.5 mg/kg); 15.22% ± 1.30 (125 mg/kg) and 9.38% ± 0.57 (250 mg/kg). Daily food intake was significantly higher (p<0.05) in the group treated with 250 mg/kg of JRLE in comparison with vehicle-dose group; the reduction in ethanol intake was associated with a compensatory increase in food intake, probably because in the control group animals a part of the total caloric intake was supplied by ethanol. Treatment was very well tolerated by all animals and without apparent side-effects. These results contribute to the scientific validation of the antialcoholic indication of this botanic species in Argentine folk medicine.

Medicinal plants used for traditional veterinary in the Sierras de Córdoba (Argentina): an ethnobotanical comparison with human medicinal uses

BACKGROUND

This is a first description of the main ethnoveterinary features of the peasants in the Sierras de Córdoba. The aim of this study was to analyze the use of medicinal plants and other traditional therapeutic practices for healing domestic animals and cattle. Our particular goals were to: characterize veterinary ethnobotanical knowledge considering age, gender and role of the specialists; interpret the cultural features of the traditional local veterinary medicine and plant uses associated to it; compare the plants used in traditional veterinary medicine, with those used in human medicine in the same region.

METHODS

Fieldwork was carried out as part of an ethnobotanic regional study where 64 informants were interviewed regarding medicinal plants used in veterinary medicine throughout 2001-2010. Based participant observation and open and semi-structured interviews we obtained information on the traditional practices of diagnosis and healing, focusing on the veterinary uses given to plants (part of the plant used, method of preparation and administration). Plants speciemens were collected with the informants and their vernacular and scientific names were registered in a database. Non-parametric statistic was used to evaluate differences in medicinal plant knowledge, use, and valorization by local people. A comparison between traditional veterinary medicine and previous human medicine studies developed in the region was performed by analyzing the percentages of common species and uses, and by considering Sorensen's Similarity Index.

RESULTS

A total of 127 medicinal uses were registered, corresponding to 70 species of plants belonging to 39 botanic families. Veterinary ethnobotanical knowledge was specialized, restricted, in general, to cattle breeders (mainly men) and to a less degree to healers, and was independent of the age of the interviewees. Native plants were mostly used as skin cicatrizants, disinfectants or for treating digestive disorders. Together with a vast repertoire of plant pharmacopoeia, the therapies also involve religious or ritualistic practices and other popular remedies that evidence the influence of traditional Hispanic-European knowledge. Although the traditional veterinary knowledge seems to be similar or else is inlcuded in the local human ethnomedicine, sharing a common group of plants, it has distinct traits originated by a constant assessment of new applications specifically destined to the treatment of animals.

CONCLUSIONS

Veterinary medicine is a fountain of relevant vernacular knowledge, a permanent source for testing new applications with valuable ethnobotanical interest. Knowledge on medicinal applications of native plants will allow future validations and tests for new homeopathic or phytotherapeutic preparations.