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The total proton and carbon-13 NMR assignments of quinghaosu I, II and V isolated from Artemisia annua cultivated in Brazil and of the synthetic derivatives quinghaosu alkene, ketone and epoxy are reported. The conformations and conformational equilibria of these compounds in solution were obtained from the spectral data and molecular mechanics calculations.

The effects of Chronic administration of the new antimalaria drug artemether on cardiovascular function were investigated in albino Sprague-Dawley rats. One group of rats received 3.2mg/kg artemether (Therapeutic dose) and a second group received 18mg/kg of artemether while the control group received vehicle (refined corn oil) for 28 days. The animals were anaesthetized thereafter and cannulated for recording of blood pressure and testing of cardiovascular reflexes. Results from the study showed that artemether had little or no effect on mean arterial pressure (MAP) both at the therapeutic and high doses compared to the controls (90.37+4.3 and 97.1+2.7mmHg respectively cf 88.35+2.6mmHg, NS). Heart rate (HR) did not change significantly in the artemether treated rats. However during bilateral carotid occlusion (BC)) the magnitude of the change in blood pressure (MAP) and heart rate (HR) were reduced in the group that received 18mg/kg artemether (41.55+2.1mmHg; p Both therapeutic and high doses of artemether reduced the index of baroreflex sensitivity in this study. The results from this study suggest that whilst artemether may not have significant effect on resting cardiovascular function, it may interfere with ability of the cardiovascular system to respond to the challenges. Key Words: Arthemether, Blood Pressure, Heart Rate, Baroreflex sensitivity [J. of Med. & Medical Sci. Vol.1(1) 1999: 50-54]

α-Arteether(12α-O-ethyldihydroartemisinin), a potent antimalarial drug, has been synthesized stereoselectively from artemisinin (qinghaosu) using Ag 2 O catalyst

In the presence of iron(II) the peroxy bridge of the drug quinghaosu and its derivatives and cleaved to give two rearrangement products; DNA damage due to this free radical process is observed an may be responsible for the antimalarial activity of these compounds.

The complete assignment of the 1H and 13C nmr signals for Qinghaosu 1 has been made. Treatment of 1 with methoxide ion at 80 °C results in bright luminescence when carried out in the presence of fluorescers. Several products are formed when methanol is present, but in toluene only one product is formed when methanol-free methoxide is used. Its structure is tentatively assigned as 1-(1-methoxycarbonylethyl)-2,6-dimethyl-2-hydroxybicyclo[3.3.1]nonan-9-one.

In order to investigate the possibility of isolating greater amounts of the antimalarial compound artemisinin (quinghaosu), plants of ARTEMISIA ANNUA were cultivated and analysed at different stages of development. We found the highest content just before flowering. It was also possible to correlate development of the plants with the maximum content of artemisinin. ARTEMISIA ANNUA plants cultivated from various other sources were also examine for artemisinin content. According to our results, none of these plants contained sufficient amounts of artemisinin to justify an isolation on a technical scale. Furthermore other Artemisia species were tested. We found artemisinin in only one other species. To possibly increase the amount of artemisinin during the growth period of the plant, we tested two hormone-type growth regulators on A. ANNUA strain 811. The results showed that one of them, chlormequat, was able to increase the artemisinin content by 30% over untreated plants. We also found some slight effects of the growth regulators on morphological criteria of glandular trichomes.

The present paper is a continuation of our study on the Chinese traditional herb Artemisia annua L. [1-5], describing several additional constituents: quinghaosu IV and V (V, VII), quinghao acid (VIII) [6], chrysosplenol (VIa) [7] and a paraffinic alcohol; V, VII and VIII are compounds with unreported structures.