Submitted to: Journal of Herbs, Spices and Medicinal Plants
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/25/2001
Publication Date: 2/15/2002
Citation: VAUGHN, S.F., TISSERAT, B., CANTRELL, C.L., BERHOW, M.A. ULTRAHIGH CARBON DIOXIDE ATMOSPHERES INCREASE THE GROWTH RATE, MORPHOGENESIS AND NAPHTHODIANTHRONE LEVELS IN ST. JOHN'S WORT (HYPERICUM PERFORATUM) PLANTS. JOURNAL OF HERBS SPICES AND MEDICINAL PLANTS. Vol. 10(2)P. 35-46. 2002. Interpretive Summary: Elevated carbon dioxide atmospheres have been found to stimulate the growth of many plants. Many plant natural products have economic importance, oftentimes as drugs or as drug precursors. St. John's Wort (Hypericum perforatum) has been used since antiquity as a medicinal plant and is sold extensively in the United States as an over-the-counter herbal remedy for depression and other ailments. Hypericin and the similar compound pseudohypericin are two of these natural products that may be the bioactive agents. In this paper, we describe the effects of elevated carbon dioxide on the growth and production of leaves, shoots and roots of St. John's Wort plants as well as tissue concentrations of hypericin and pseudohypericin. We also report modified methods for the isolation of purified hypericin and pseudohypericin, and also describe a simplified method for quantifying these natural products in crude extracts of plant material. Enriched carbon dioxide atmospheres therefore could allow the greenhouse culture of plants producing high-value natural products for U.S. producers in an economically-viable fashion.
Technical Abstract: Growth (fresh weight), morphogenesis (formation of leaves, roots and shoots) and tissue concentrations of the naphthodianthrones hypericin and pseudohypericin were determined in St. John's Wort (Hypericum perforatum L.) plants grown for 8 weeks under 350, 1500, 3000, 10,000, and 30,000 microliters CO2 L(-1) atmospheres. Plants were grown from shoot cuttings in a vermiculite-peat moss mixture within a greenhouse employing natural sunlight. Elevated CO2 levels [greater than/equal to 1500 microliters CO2 L(-1)] significantly increased growth and morphogenesis compared to ambient (350 microliters CO2 L(-1) levels. Modified procedures for the purification of naphthodianthrone standards and their quantitation were developed. Levels of hypericin were significantly higher at 1500 and 3000 microliters CO2 L(-1) than at ambient CO2, while the higher [10,000 and 30,000 microliters CO2 L(-1)] CO2 atmospheres caused reductions in levels of both naphthodianthrones in plant tissues. However, because of increased plant growth, naphthodianthrone yields were significantly increased at elevated CO2 levels compared to controls.