Residues and contaminants in medicinal herbs—A review

With the increasing popularity and use of medicinal herbs, their global demand has gained momentum. Developing countries, including China, India and South East Asian (SEA) countries, are the centres of origin and major global suppliers for most of these traditionally used medicinal herbs. One of the factors affecting the quality of these herbs is the contamination of heavy metals, mycotoxins, pesticide residues, polycyclic aromatic hydrocarbons (PAHs) and fumigants. These contaminants can accumulate during the cultivation, storage and processing of herbs and may have adverse effects on consumer health. There have been various reports regarding the presence of these contaminants in medicinal herbs. This review discusses the important contaminants of medicinal herbs, the frequency and magnitude of their occurrences, the potential causes of contamination and their regulatory limits in medicinal herbs. The major challenge in the international trade of medicinal herbs is the lack of common guidelines, regulatory measures and monitoring body to strictly enforce their regulation.     

The forest resources input–output model: An application in China

Understanding the state of forest resource utilization in China and correctly evaluating the role and function of forest resources in national economic development are essential for realizing balanced development of forests, the environment, and the economy. This is especially true given the present situation of increasingly scarce forest resources. Using data from Chinese forest industry statistical yearbooks, forestry development reports, and other documents, this paper examines the current state of forest resource utilization in China from the angle of combining quantities and values based on input–output tables. We show that demand for and input use of forest resources varies greatly across industrial sectors; the paper products and furniture manufacturing industries have the greatest direct consumption coefficient for timber use. When considering direct and indirect demand, it is clear that forest resources restrict different industrial sectors in diverse ways. These results provide an important set of reference values regarding the utilization of forest resources and coordinated industrial development in China.     

Lability of fat stores in peripubertal wild house mice

Summary Traditionally, the adaptive value of mammalian white fat stores is considered in relation to longterm needs such as providing protection against the vagaries of winter or signalling the reproductive system when energy reserves are sufficient to risk pregnancy. As shown here, the fat stores of young house mice could not serve such needs. Despite prolonged acclimation and excess nesting material, food deprivation at 10°C significantly lowered the fat stores of peripubertal female house mice in only 12 h, and would exhaust them in 30 h. Even close to thermoneutrality (24°C) the calculated time to exhaustion was only 70 h. The fat stores of a young house mouse are obviously too meager to offer any meaningful protection over a winter of several months duration, or even over a 5–6-week cycle of pregnancy and lactation. Furthermore, in a wild habitat where food availability and ambient temperature can vary rapidly and greatly, such fat stores would be too labile to effectively coordinate puberty with somatic development.     

Saldanha Bay,South Africa: recovery of Gracilaria verrucosa (Gracilariales,Rhodophyta)

Since World War II the greater Saldanha Bay lagoon system, South Africa, has been an important Gracilaria producer. Two agar factories, built in the 1960's, used Gracilaria from Saldanha Bay as their raw material. In the early 1970's the industry was destroyed as a result of dredging and marine construction operations to establish a harbor in the bay for loading ore. These environmental changes destroyed stocks and prevented the previously significant beachings of the seaweed from occurring. After a few years of no or very low commercial production, the resource slowly started to recover. The size of Gracilaria drifts increased over the following eight years to approximately one-third of the original output. This trend seems to continue. Although the stocks and resultant drifts are unlikely to recover fully to their original quantity, current production is already sufficient to ensure re-establishment of a seaweed industry in Saldanha Bay. This could have considerable socio-economic impact on the area.     

The Importance of Amine-degrading Enzymes on the Biogenic Amine Degradation in Fermented Foods: A review

Biogenic amines (BAs) are a class of harmful compounds often be found in high protein foods, especially naturally fermented foods. BAs derive from free amino acid decarboxylation through microbial activities and can cause toxic effects (headache, heart palpitations, vomiting) on humans, depending on individual sensitivity. Indigenous amine-degrading strains or strains producing amine-degrading enzymes (ADEs) have drawn great attention since they play an important role in affecting BA accumulation, and enzymes/genes involved in the biosynthetic mechanisms. They also help maintain the sensory quality of the final products. Besides, due to ADEs’ harmless catalytic products, they can be further utilized in fermented foods and beverages to reduce BAs. This review describes in detail the mechanisms of BAs formation, as well as the diversity of ADEs able to degrade BAs in a model or real food systems. A deeper knowledge of this issue is crucial because ADEs’ activities are often associated with strains rather than species or genera. Moreover, this information can help to improve the selection and characterization of strains for further applications as starters or bioprotective cultures, to obtain high-quality foods with reduced BAs contents.     

Fusarium oxysporum f. sp. strigae strain Foxy 2 did not achieve biological control of Striga hermonthica parasitizing maize in Western Kenya

The production of maize, a major staple food crop in sub-Saharan Africa is being constrained by the parasitic weed Striga hermonthica. The fungus Fusarium oxysporum f. sp. strigae (Foxy 2) that causes fusarium wilt of Striga in Ghana, West Africa, is being considered for biological control of the weed in Western Kenya. The present study investigated the efficacy of F. oxysporum f. sp. strigae (Foxy 2) for S. hermonthica management in Western Kenya. Research was conducted in post-entry quarantine (PEQ) facilities at Alupe, Busia, Homabay, Kibos and Siaya field stations for two seasons. Each PEQ was a split-plot, with 4 main blocks each having 6 treatment subplots. The treatments included seeds of two S. hermonthica-susceptible maize varieties, either coated with Foxy 2 using gum Arabic, gum Arabic alone, or left untreated. Data was collected over seven sampling periods on S. hermonthica population per plant, percentage of those that were wilting, and the severity of wilting. Maize plant growth parameters assessed included duration to 50% anthesis and 50% silking, plant height, number of leaves, stover and cob weights, and maize yield per hectare. Statistical analysis was done using SAS 9.1 software. Data on S. hermonthica population were analyzed by χ²-test using Proc Genmod (Poisson); while the other parameters were analyzed by Proc Mixed using study location, season and blocks as random effects, and the sampling periods as repeated effects. All the assessed parameters were similar between plants grown from seeds inoculated with F. oxysporum f. sp. strigae (Foxy 2), those coated with gum Arabic, and the ones without any coating. These parameters were also not different between the maize varieties. There are varying reasons for the disparities between results on F. oxysporum f. sp. strigae (Foxy 2) obtained in this Kenyan study, and those from researches outside this country. In conclusion, F. oxysporum f. sp. strigae strain Foxy 2 is predominantly safe on maize growth, but its efficacy in controlling S. hermonthica was not evident on the tested Kenyan soils.     

Breeding biology, resource partitioning and reproductive effort of a dioecious shrub, Clutia pulchella L. (Euphorbiaceae)

 The flowering of Clutia pulchella was studied in a coastal scarp forest community in southern KwaZulu-Natal, South Africa. Sex dependent differences in the frequency and magnitude of floral output were recorded, with male individuals producing 4.32 times more flowers per leaf axis than females. Increased node production, as a manifestation of significantly increased branching, allowed for prolific flower production in males. Energy investment per flower was marginally greater in females (0.045 J/mg), despite copious pollen production and glandular secretion in males (0.035 J/mg). Differential flower production, reproductive organ dry mass and an unbalanced branching ratio revealed that “per plant” expenditure towards flowering was more pronounced in males (♀ flowering × 5.04). The elevated cost of fruit production (♀ flowering × 5.5), inclusive of imperfect fruit set, resulted in overall reproductive expense being slightly higher for females. Such sex-dependent reproductive investment was shown to have minimal influence on the population sex ratio, with sex frequencies and nearest neighbor distances yielding a non-significant male bias of 1.16. No evidence of spatial asymmetry was found. Received December 1, 1999 Accepted September 27, 2000     

Negative density-dependent emigration of males in an increasing red deer population

In species with polygynous mating systems, females are regarded as food-limited, while males are limited by access to mates. When local density increases, forage availability declines, while mate access for males may increase due to an increasingly female-biased sex ratio. Density dependence in emigration rates may consequently differ between sexes. Here, we investigate emigration using mark-recovery data from 468 young red deer Cervus elaphus marked in Snillfjord, Norway over a 20-year period when the population size has increased sixfold. We demonstrate a strong negative density-dependent emigration rate in males, while female emigration rates were lower and independent of density. Emigrating males leaving the natal range settled in areas with lower density than expected by chance. Dispersing males moved 42 per cent longer at high density in 1997 (37 km) than at low density in 1977 (26 km), possibly caused by increasing saturation of deer in areas surrounding the marking sites. Our study highlights that pattern of density dependence in dispersal rates may differ markedly between sexes in highly polygynous species. Contrasting patterns reported in small-scale studies are suggestive that spatial scale of density variation may affect the pattern of temporal density dependence in emigration rates and distances.