Water quality effects of clearcut harvesting and forest fertilization with best management practices.

Nine small (2.5 ha) and four large (70-135 ha) watersheds were instrumented in 1999 to evaluate the effects of silvicultural practices with application of best management practices (BMPs) on stream water quality in East Texas, USA. Two management regimes were implemented in 2002: (i) conventional, with clearcutting, herbicide site preparation, and BMPs and (ii) intensive, which added subsoiling, aerial broadcast fertilization, and an additional herbicide application. Watershed effects were compared with results from a study on the same small watersheds in 1981, in which two combinations of harvesting and mechanical site preparation without BMPs or fertilization were evaluated. Clearcutting with conventional site preparation resulted in increased nitrogen losses on the small watersheds by about 1 additional kg ha(-1) each of total Kjeldahl nitrogen (TKN) and nitrate-nitrogen (NO(3)-N) in 2003. First-year losses were not significantly increased on the large watershed with a conventional site preparation with BMPs. Fertilization resulted in increased runoff losses in 2003 on the intensive small watersheds by an additional 0.77, 2.33, and 0.36 kg ha(-1) for NO(3)-N, TKN, and total phosphorus, respectively. Total loss rates of ammonia nitrogen (NH(4)-N) and NO(3)-N were low overall and accounted for only approximately 7% of the applied N. Mean loss rates from treated watersheds were much lower than rainfall inputs of about 5 kg ha(-1) TKN and NO(3)-N in 2003. Aerial fertilization of the 5-yr-old stand on another large watershed did not increase nutrient losses. Intensive silvicultural practices with BMPs did not significantly impair surface water quality with N and P.

Flavonoids, coumarins and triterpenes from the aerial parts of Cnidoscolus texanus.

Phytochemical investigation on Cnidoscolus texanus led to the isolation of 26 compounds, which included 15 flavonoids (1-15), three coumarins (16-18), three coumaric acid derivatives (19-21), four triterpenoids (22-25), and one phytosterol (26). Among them, aromadendrin 7-O-(4''-O-P-E-coumaroyl-beta-glucopyranoside) (1), aromadendrin 7-O-(3'',6''-di-O-P-E-coumaroyl-beta-glucopyranoside) (2), and naringenin 7-O-(4''-O-P-Z-coumaroyl-beta-glucopyranoside) (3) are new compounds. Their structures were determined by spectroscopic and chemical methods. All flavonoids were found to be inactive against DNA topoisomerase I.

New camptothecin and ellagic acid analogues from the root bark of Camptotheca acuminata.

As part of a study on chemical constituents of Camptotheca species, one new natural camptothecin analogue (2), two new alkaloids (3, 4), one new ellagic acid analogue (5), and 19 known compounds (1, 6-23) have been isolated from the root bark, stem bark, fruits, and leaves of Camptotheca acuminata Decaisne. The structures of 2-5 were determined from spectral data to be 10-methoxy-20-O-acetylcamptothecin (2), 20-O-beta-glucopyranosyl 18-hydroxycamptothecin (3), 20-formylbenz indolizino [1,2-b]quino-line-11(13H)-one (4), and 3,4-methylenedioxy-3'-O-methyl-5'-hydroxyellagic acid (5).

Camptothecin accumulation and variations in camptotheca.

Camptotheca (Nyssaceae) is a major source of anticancer camptothecin (CPT). It is imperative to understand CPT accumulation and variations in Camptotheca in order to develop CPT production strategies for endangered germplasm. Our study results showed that CPT is primarily accumulated in glandular trichomes of leaves and stems, and CPT content varies among species and varieties but even more significantly within the plant (with different tissues, tissue ages, and seasons). Because of higher CPT yield and desirable biological and ecological features, 'Hicksii' and 'Katie' should be considered the major management germplasm as CPT sources in the future. Young leaves and mature fruits have higher CPT contents than other tissues in the plants. Young photosynthetic leaves and stems contain higher CPT contents than old ones, but 'sink' tissues such as wood, roots, and fruits show different patterns. CPT content also shows a great seasonal change, but is less influenced by tree age. Intact clipping of young leaves and stems should be managed for harvest for CPT production. Preservation and treatment methods influence the CPT extraction. CPT is better preserved in fresh or freeze-dried material than in air or oven-dried material. CPT can be more efficiently extracted after homogenizer treatment of plant materials because more trichome walls can be broken to allow solvent extraction.