Tom J. Mabry

Bio: Tom J. Mabry is an academic researcher from University of Texas at Austin. The author has contributed to research in topic(s): Kaempferol & Sesquiterpene lactone. The author has an hindex of 42, co-authored 459 publication(s) receiving 13375 citation(s). Previous affiliations of Tom J. Mabry include University of Illinois at Urbana–Champaign & Minia University.

Carbon-13 NMR studies of flavonoids. III. Naturally occurring flavonoid glycosides and their acylated derivatives

Abstract: 13 C NMR spectra for a variety of flavonoid glycosidcs are presented and analysed. Evidence is presented which demonstrates that 13 C NMR spectroscopy is a valuable technique for distinguishing the sites of methylation, glycosylation and acylation in flavonoid glycoiides, and in some cases the nature and sites of specific sugars and acyl groups. Shifts observed in the spectrum on derivization of the 5-OH group are unusual. The ring size and C-1 configuration in glycosidic sugars are also evident from the spectra. Structural assignments are made for several glycoides.

The Ultraviolet Spectra of Flavones and Flavonols

Abstract: The methanol spectra of flavones and flavonols exhibit two major absorption peaks in the region 240 – 400 nm1. These two peaks are commonly referred to as Band I (usually 300 – 380 nm, Table V-1 records the λmaxvalues for Band I for all flavones and flavonols examined in the present investigation), and Band II (usually 240 – 280 nm). Band I is considered to be associated with absorption due to the B-ring cinnamoyl system, and Band II with absorption involving the A-ring benzoyl system (see III) [1].

Ultraviolet-Visible and Proton Magnetic Resonance Spectroscopy of Flavonoids

Abstract: A number of reviews of ultraviolet and visible absorption spectroscopy have appeared in the past (Jurd, 1962; Mabry et al., 1970; Swain, 1965; Mabry, 1969; Harborne, 1963) the most comprehensive being those of Jurd (1962) and Mabry et al., (1970). The article by Jurd summarizes the work in this field up to about 1960 and gives detailed references to the original spectroscopic work carried out with flavonoids. The book by Mabry et al (1970) updates Jurd’s chapter and in addition provides a detailed catalogue of the ultraviolet (UV) spectra of 175 flavonoids together with comprehensive data on reagent induced shifts for each flavonoid. The present article includes some of the more significant aspects of the earlier reviews and in addition brings them up to date.

Structure-antioxidant activity relationships of flavonoids and phenolic acids

Abstract: The recent explosion of interest in the bioactivity of the flavonoids of higher plants is due, at least in part, to the potential health benefits of these polyphenolic components of major dietary constituents. This review article discusses the biological properties of the flavonoids and focuses on the relationship between their antioxidant activity, as hydrogen donating free radical scavengers, and their chemical structures. This culminates in a proposed hierarchy of antioxidant activity in the aqueous phase. The cumulative findings concerning structure-antioxidant activity relationships in the lipophilic phase derive from studies on fatty acids, liposomes, and low-density lipoproteins; the factors underlying the influence of the different classes of polyphenols in enhancing their resistance to oxidation are discussed and support the contention that the partition coefficients of the flavonoids as well as their rates of reaction with the relevant radicals define the antioxidant activities in the lipophilic phase.

An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II

Abstract: A revised and updated classification for the families of the flowering plants is provided. Newly adopted orders include Austrobaileyales, Canellales, Gunnerales, Crossosomatales and Celastrales. Pertinent literature published since the first APG classification is included, such that many additional families are now placed in the phylogenetic scheme. Among these are Hydnoraceae (Piperales), Nartheciaceae (Dioscoreales), Corsiaceae (Liliales), Triuridaceae (Pandanales), Hanguanaceae (Commelinales), Bromeliacae, Mayacaceae and Rapateaceae (all Poales), Barbeuiaceae and Gisekiaceae (both Caryophyllales), Geissolomataceae, Strasburgeriaceae and Vitaceae (unplaced to order, but included in the rosids), Zygophyllaceae (unplaced to order, but included in eurosids I), Bonnetiaceae, Ctenolophonaceae, Elatinaceae, Ixonanthaceae, Lophopyxidaceae, Podostemaceae (Malpighiales), Paracryphiaceae (unplaced in euasterid II), Sladeniaceae, Pentaphylacaceae (Ericales) and Cardiopteridaceae (Aquifoliales). Several major families are recircumscribed. Salicaceae are expanded to include a large part of Flacourtiaceae, including the type genus of that family; another portion of former Flacourtiaceae is assigned to an expanded circumscription of Achariaceae. Euphorbiaceae are restricted to the uniovulate subfamilies; Phyllanthoideae are recognized as Phyllanthaceae and Oldfieldioideae as Picrodendraceae. Scrophulariaceae are recircumscribed to include Buddlejaceae and Myoporaceae and exclude several former members; these are assigned to Calceolariaceae, Orobanchaceae and Plantaginaceae. We expand the use of bracketing families that could be included optionally in broader circumscriptions with other related families; these include Agapanthaceae and Amaryllidaceae in Alliaceae s.l. , Agavaceae, Hyacinthaceae and Ruscaceae (among many other Asparagales) in Asparagaceae s.l. , Dichapetalaceae in Chrysobalanaceae, Turneraceae in Passifloraceae, Erythroxylaceae in Rhizophoraceae, and Diervillaceae, Dipsacaceae, Linnaeaceae, Morinaceae and Valerianaceae in Caprifoliaceae s.l. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 399‐436.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

Abstract: Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

Resource Availability and Plant Antiherbivore Defense

Abstract: The degree of herbivory and the effectiveness of defense varies widely among plant species. Resource availability in the environment is proposed as the major determinant of both the amount and type of plant defense. When resource are limited, plants with inherently slow growth are favored over those with fast growth rates; slow rates in turn favor large investments in antiherbivore defenses. Leaf lifetime, also determined by resource availability, affects the relative advantages of defenses with different turnover rates. Relative limitation of different resources also constrains the types of defenses. The proposals are compared with other theories on the evolution of plant defenses.

Estimation of total flavonoid content in propolis by two complementary colorimetric methods

Abstract: Flavonoids, with various biological activities, are considered as key compounds in propolis. In this study, quantitative deter minations of flavonoids in propolis were conducted by two complementary colorimetric methods, aluminum chloride method and 2,4-dini trophenylhydrazine method. Results suggested that the sum of flavonoid contents determined by the above two individual methods ma y represent the real content of total flavonoids. In this work, six raw propolis samples were investigated and the total content s of flavonoids ranged from 10.38 ± 0.14% to 24.91 ± 0.53%. As for the 12 commercial propolis products examined, the levels of total flavonoids in tinctures were all below 7% and those in powdery products varied from 2.97 ± 0.05% to 22.73 ± 0.72%.