Protection of immunocompromised mice from fungal infection with a thymus growth-stimulatory component from Selaginella involvens, a fern.

CONTEXT: Recent studies have shown that the water extract of Selaginella involvens (Sw.) Spring, a wild fern, exhibits thymus growth-stimulatory activity in adult mice (reversal of involution of thymus) and remarkable anti-lipid peroxidation activity. Follow-up studies were carried out in the present study. MATERIALS AND METHODS: Activity-guided isolation of the active component (AC) was carried out. The effect of AC on immune function was studied using fungal (Aspergillus fumigatus) challenge in cortisone-treated mice. The in vitro antifungal activity of AC was assayed using disc diffusion assay. In vitro and in vivo effect of AC on DNA synthesis in thymus was studied using (3)H-thymidine incorporation. In in vitro anti-lipid peroxidation, hydroxyl radical scavenging and inhibition of superoxide production were assayed. RESULTS: The active principle/component (AC) was isolated in a chromatographically pure form from the water extract of S. involvens. AC showed positive reaction to glycosides. AC possessed both thymus growth-stimulatory and antioxidant properties. It protected cortisone-treated mice from A. fumigatus challenge. It did not exhibit in vitro antifungal activity. Increased (3)H-thymidine incorporation was observed in the reticuloepithelium of thymus obtained from AC-treated mice. However, in vitro AC treatment to thymus for 5 h did not result in an increase in (3)H-thymidine incorporation. DISCUSSION AND CONCLUSION: AC (named as Selagin), from S. involvens, could reverse involution of thymus to a large extent, exhibit remarkable antioxidant activity, and protect immunocompromised mice from fungal infection. Therefore, it is very promising for the development of a drug to ameliorate old age-related health problems and prolong lifespan.

In vitro cross-reactivity between tomato and other plant allergens.

BACKGROUND: Cross-reactivity among fruits and different pollen and fruit species has been extensively reported. OBJECTIVES: To investigate the in vitro cross-reactivity between tomato and pollen, fruit, and latex extracts and to identify the proteins involved. METHODS: A serum pool was prepared from 18 individuals residing on the Spanish Mediterranean coast (9 men and 9 women; mean [SD] age, 27.4 [10.1] years) who had positive skin prick test reactions to tomato peel. Extracts from 10 pollens, 12 fruits, and latex were tested. Levels of specific IgE to each extract were measured. The allergenic profile was evaluated by means of immunoblot. The percentage of inhibition between extracts and tomato peel extract was analyzed by means of CAP inhibition, and the allergens implicated were elucidated by immunoblot inhibition. RESULTS: For pollens, the highest specific IgE values were obtained for grasses. Most pollen extracts showed a capacity of inhibition similar to that of tomato peel extract; high percentages were obtained with Artemisia vulgaris and Poa pratensis. The most strongly inhibited allergens in tomato corresponded to bands of 32 and 45 kDa. For fruits, the highest value of specific IgE was detected for peach. High percentages of inhibition were obtained with peach and hazelnut. No inhibition was detected with latex. Peach, chestnut, and melon inhibited high molecular weight bands (32 and 45 kDa) and a band of approximately 10 kDa. CONCLUSIONS: Cross-reactivity between tomato and pollen and fruit extracts has been demonstrated. Allergens with a high molecular weight range seem to be responsible in pollen extracts. A 10-kDa band seems to be responsible in Platanus acerifolia, Salsola kali, peach, chestnut, and melon.