Antimalarial diterpenoids from Vitex rotundifolia: Isolation, structure elucidation, and in vitro antiplasmodial activity

Vitex rotundifolia is an important medicinal plant frequently employed in traditional medicines for the treatment of various ailments. Although this plant species has been under exploration for its constituents by various research groups including our own group, no reports were found regarding the antimalarial potential of this plant or of its purified phytochemicals. Phytochemical investigation of this plant yielded three new (1-3) and five known (4-8) diterpenoids. These compounds were purified by modern chromatographic techniques and their structures were determined by advanced spectroscopic techniques such as nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). The in vitro antiplasmodial activities were encouraging, as compounds 2, 6, and 8 were found to have significant IC₅₀ values of 1.2, 1.3 and 11.0 µM, respectively against Plasmodium falciparum.

Isolation and characterization of antiplasmodial constituents from the marine sponge Coscinoderma sp

Six known compounds, namely two halisulfates 1 and 2 and four epidioxy sterols 3-6, were isolated from the marine sponge Coscinoderma sp. The structures of these compounds were confirmed by nuclear magnetic resonance (1H and 13C NMR) spectroscopy, and their antiplasmodial activities were determined against the chloroquine-resistant Dd2 strain of Plasmodium falciparum. The epidioxy steroids 3-6 all showed moderate to weak antiplasmodial activity, with IC50 values of 2.7 μM for (24S)-5α,8α-epidioxy-24-methylcholesta-6-en-3β-ol (3), 11.6 μM for 5α,8α-epidioxycholesta-6,24(28)-dien-3β-o1 (4), 2.33 μM for 5α,8α-epidioxy-24-methylcholesta-6,9(11)-24(28)-trien-3β-ol (5), and between 12 and 24 μM for 5α,8α-epidioxycholesta-6-en-3β-ol (6). In contrast, halisulfate 2 (1) was inactive, and halisulfate 1 (2) had an of IC50 value of about 24 μM.

Antimalarial activity of the isolates from the marine sponge Hyrtios erectus against the chloroquine-resistant Dd2 strain of Plasmodium falciparum

This work reports the isolation of the three known compounds, smenotronic acid (1), ilimaquinone (2), and pelorol (3), from the 85% methanol (MeOH)-soluble fraction of the sponge Hyrtios erectus. The structures of the isolated compounds were determined with the help of modern spectroscopic techniques, and the resulting compounds were then subjected to in vitro screening to determine their antimalarial potential against the chloroquine-resistant Dd2 strain of Plasmodium falciparum. Amongst the three compounds, pelorol (3) showed significant activity against P. falciparum with an IC50 value of 0.8 μM. For smenotronic acid (1) and ilimaquinone (2), moderate activities were observed with IC50 values of 3.51 and 2.11 μM, respectively.

Bioactive Neolignans and Other Compounds from Magnolia grandiflora L.: Isolation and Antiplasmodial Activity

Bioassay-guided fractionation of a methanol extract of Magnolia grandiflora against Plasmodium falciparum yielded two new (1 and 2) and six known (3 - 8) bioactive compounds. The structures of the new compounds were assigned by mass spectrometric and 1D- and 2D-NMR data. Known compounds were identified by comparison of ¹ H-NMR and MS data with literature data. The two known neolignans 3 and 4 showed moderate antiplasmodial activity with the IC₅₀ values of 2.8 ± 0.1 and 3.4 ± 0.1 μm, respectively. Weak antiplasmodial activity was recorded for compounds 1, 2, 5, 6, 7, and 8, with the IC₅₀ values of 38 ± 2, 23 ± 2, 16.5 ± 0.2, 86 ± 1, 44 ± 4, and 114 ± 9 μm, respectively.

Autopsy study of pediatric deaths

OBJECTIVE

Childhood autopsies occurring during January 1997 to December 1999 were reviewed.

METHOD

Of the total 1,445 deaths autopsied, 441 (30.5%) were of pediatric patients.

RESULT

Of these deaths, 70.3% occurred during neonatal period, 8.6% in infancy, and 21.1% in childhood. Birth asphyxia (57.7%) was the most frequent mode of death in the neonatal period. Infections (67.2%) predominantly accounted for infant and childhood mortality, those of respiratory tract (46.1%) being most frequent in infancy, early and mid childhood, and enteric fever in late childhood (33.3%). Discrepancy between ante-mortem and post-mortem diagnosis occurred in 29 cases (6.6%).

CONCLUSION

Autopsy is an important clinical tool providing useful information to the physician. Few published reports are available on pediatric autopsies. This study aims to help in a better understanding of causes of deaths in neonates, infants and children.

An activating mutation in the gamma1 subunit of the AMP-activated protein kinase

The AMP-activated protein kinase (AMPK) is a heterotrimeric protein composed of a catalytic alpha subunit and two regulatory subunits, beta and gamma. The gamma subunit is essential for enzyme activity by virtue of its binding to the C-terminus of the alpha subunit and appears to play some role in the determination of AMP sensitivity. We demonstrate that a gamma1R70Q mutation causes a marked increase in AMPK activity and renders it largely AMP-independent. This activation is associated with increased phosphorylation of the alpha subunit activation loop T172. These in vitro characteristics of AMPK are also reflected in increased intracellular phosphorylation of one of its major substrates, acetyl-CoA carboxylase. These data illustrate the importance of the gamma1 subunit in the regulation of AMPK and its modulation by AMP.