Phytochemical Composition of Commiphora Oleogum Resins and Their Cytotoxicity against Skin Cancer Cells

Oleogum resins of the genus Commiphora have been used in traditional medicines for centuries. More than 200 Commiphora species exhibit highly variable phytochemical compositions. A novel highly selective, sensitive, accurate HPLC-MS/MS method was developed and validated to quantify five characteristic phytosteroids and furanosesquiterpenoids, namely (E)-guggulsterone, (Z)-guggulsterone, curzerenone, furanoeudesma-1,3-diene, and myrrhone. The resulting contents and additionally GC analysis were used to classify and differentiate Commiphora oleogum resins of the species C. myrrha, C. erythraea, C. mukul, C. holtziana, C. confusa, and C. kua, as well as unspecified resins. Interestingly, a Commiphora sample from Ogaden, Ethiopia, comprised 446 ng/mg guggulsterones presumed to be unique to C. mukul from the Indian subcontinent. However, Commiphora from Ogaden differed considerably from C. mukul in respect to guggulsterones isomer’s ratio. Moreover, the cytotoxicity of Commiphora extracts, essential oils, botanical drugs containing Commiphora, and pure compounds against the epidermoid carcinoma A431, malignant melanoma RPMI-7951 and SK-MEL-28 cells was investigated in vitro. Thereby, especially C. mukul extract and C. myrrha essential oil exhibited high cytotoxicity against skin cancer cells with IC₅₀ of 2.9–10.9 µg/mL, but were less toxic to normal keratinocytes. In summary, Commiphora oleogum resins and its phytochemicals warrant further investigation aiming at chemotaxonomical classification as well as application in skin cancer treatment.     

Secondary sonochemical effect on Mo-catalyzed bromination of aromatic compounds

The Molybdate-catalyzed bromination of various aromatic compounds in the presence of KBr/H(2)O(2) in an aqueous/chloroform biphasic system occurred under ultrasonic irradiation, whereas the reaction did not take place under conventional mechanical stirring (1400 rpm). The sonochemical activation was found to be of secondary effect, attributed to lowering pH by sonolysis of CHCl(3)-H(2)O solvents mixture.     

Use of the plant Bellardia trixago for the enantiospecific synthesis of odorant products

An easy procedure to obtain extracts enriched in trixagol monomalonylesther (1) from aerial parts of the plant Belladia trixago chemotype Trix was developed. Preparation of (+)-dihydro-gamma-ionone (4) was carried out directly from the extracts with good yields by selective oxidation. Other interesting odorant products as alpha-ambrinol (5), ambraldehyde (6) and the tricyclic compound 7 were synthesized very efficiently using (4) as intermediate.     

Synthesis and antiplasmodial activity of streptocyanine/peroxide and streptocyanine/4-aminoquinoline hybrid dyes

Two series of streptocyanine dyes incorporating cyclic peroxide or 4-aminoquinoline moieties are prepared and X-ray diffraction structures for three compounds are determined. All hybrid dyes show good antiplasmodial activity (0.06 to 0.66 μM) and are not or are slightly cytotoxic, except 10a.     

Controlling fullerene addition sequences, regioselectivity and magic numbers via metal encapsulation

A systematic density functional study of chlorine addition to C(70) up to C(70)Cl(12) confirms experimental observations of regioselectivity and stability of C(70)Cl(10). We show that K@C(70) follows an alternative addition sequence with different isomers and magic numbers to C(70) such as KC(70)Cl(3). This prediction is important for controlling functionalisation behaviour via encapsulation and endofullerene purification.     

On global motions of a compressible barotropic and selfgravitating gas with density-dependent viscosities

We consider the Cauchy problem for the equations of selfgravitating motions of a barotropic gas with density-dependent viscosities μ(ρ), and λ(ρ) satisfying the Bresch–Desjardins condition, when the pressure P(ρ) is not necessarily a monotone function of the density. We prove that this problem admits a global weak solution provided that the adiabatic exponent γ associated with P(ρ) satisfies ${\gamma > \frac{4}{3}}$ .     

Regioselectivity and mechanism of dihalocarbene addition to benzocyclopropene

Dihalocarbenes add regioselectively to aryl-substituted benzocyclopropenes to produce dihalobenzocyclobutenes. The regioselectivity of addition is not due to steric effects but depends on the electronic donor or acceptor ability of the substituent. B3LYP/6-31G* calculations show preferential :CCl2 addition to substituted benzocyclopropene through electrophilic attack on the benzocyclopropene pi-system (Ea = 1.1-2.4 kcal/mol) rather than C-C sigma-bond insertion into the cyclopropenyl moiety (Ea = 5-24 kcal/mol). pi-Addition proceeds regioselectively through a single transition state to xylylene intermediates or directly to benzocyclobutene products.     

Incorporation of N-heterocyclic cations into proteins with a highly directed chemical modification

N-Heterocyclic cations are incorporated into proteins using 5-(2-bromoethyl)phenanthridinium bromide, which selectively reacts with either cysteine or lysine residues, resulting in ethylphenanthridinium (Phen) or highly stable cyclised dihydro-imidazo-phenanthridinium (DIP) adducts respectively; these modifications have been found to manipulate the observed structure of lysozyme and bovine serum albumin by AFM.     

Strong Traces for Solutions to Scalar Conservation Laws with General Flux

In this paper we consider bounded weak solutions u of scalar conservation laws, not necessarily of class BV, defined in a subset . We define a strong notion of trace at the boundary of reached by L ¹ convergence for a large class of functionals of u, G(u). The functionals G depend on the flux function of the conservation law and on the boundary of . The result holds for a general flux function and a general subset.