BEGIN:VCALENDAR VERSION:2.0 X-WR-CALNAME:EventsCalendar PRODID:-//hacksw/handcal//NONSGML v1.0//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:America/New_York LAST-MODIFIED:20240422T053451Z TZURL:https://www.tzurl.org/zoneinfo-outlook/America/New_York X-LIC-LOCATION:America/New_York BEGIN:DAYLIGHT TZNAME:EDT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 DTSTART:19700308T020000 RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU END:DAYLIGHT BEGIN:STANDARD TZNAME:EST TZOFFSETFROM:-0400 TZOFFSETTO:-0500 DTSTART:19701101T020000 RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU END:STANDARD END:VTIMEZONE BEGIN:VEVENT CATEGORIES:College of Arts and Sciences,Thesis/Dissertations DESCRIPTION:Title: Phytochemical Characterization, Antioxidant Interactions , and Acetylcholinesterase Inhibitory Activities of Cranberry Polyphenol F ractions Advisor: Dr. Catherine Neto, Chemistry & Biochemistry Dept. Commi ttee Members: Dr. Shuowei Cai, Chemistry & Biochemistry Dept.;  Dr. Brian Blanchette, Chemistry & Biochemistry Dept. ABSTRACT Cranberries (Vacciniu m macrocarpon) are polyphenol-rich fruits containing diverse bioactive com pounds that possess antioxidant properties that can target a variety of bi ological outcomes. Although synergistic interactions have been widely repo rted in multi-herb formulas, little is known about the interactions among isolated cranberry polyphenolic fractions. The present study aimed to inve stigate the phytochemical composition, antioxidant activity, synergistic i nteractions, and acetylcholinesterase inhibitory potential of polyphenol-e nriched fractions isolated from Early Black (EB) and Mullica Queen (MQ) cr anberry cultivars. Crude cranberry extracts were fractionated using Diaion HP-20 and Sephadex LH-20 chromatography to isolate phytochemically distin ct fractions which were characterized by high-performance liquid chromatog raphy with diode array detection (HPLC-DAD), while selected proanthocyanid in (PAC)-rich fractions were further characterized by matrix-assisted lase r desorption-ionization-time-of-flight mass spectrometry (MALDI-TOF MS). A ntioxidant activities were evaluated using 2,2-diphenyl-1-picrylhydrazyl ( DPPH), 2,2’-azionbis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), an d ferric reducing power (FRAP) assays. Fractions rich in flavonol glycosid es and proanthocyanidins showed the most promising activity and were teste d independently and as binary combinations (1:1, 2:1, and 1:2) to evaluate their combined effects. These combinations were examined using both a sin gle-concentration effect-based model and a dose-response Combination Index (CI) analysis to determine synergistic, additive, or antagonistic interac tions. The effect-based model identified synergistic behavior between flav onol glycoside and PAC-rich fractions as well as between phenolic acid/ an thocyanin-rich fractions and PAC-rich fractions with relative reducing pow er (RRP) values ranging from 1.01-1.56, whereas radical scavenging activit y (RSA) of the mixtures were considered mainly antagonistic with values ra nging from 0.67-1.13. The second model instead suggested that most binary combinations exhibited mainly additive effects across all antioxidant assa ys except for a 1:1 combination of MQ A I + M IV, which showed moderate sy nergistic activity for scavenging ABTS (CI = 0.57). Selected fractions wer e also evaluated for acetylcholinesterase inhibitory activity, with the PA C-enriched fraction, MQ A I, exhibiting the greatest inhibitory activity a gainst acetylcholinesterase with an IC50 value of 21.1 mg/mL. Results of t his study demonstrate that antioxidant interactions among isolated cranber ry polyphenol fractions depends on phytochemical composition, mixing ratio , and mechanism tested. Understanding and exploiting these interactions ma y enhance their biological advantage while optimizing the bioactive compou nds required to achieve desired effects.  \nEvent page: https://www.umass d.edu/events/cms/8-4-26-defense-by-elena-de-pra-phytochemical-characteriza tion-antioxidant-.php X-ALT-DESC;FMTTYPE=text/html:

Title: Phytochemical Characteri zation\, Antioxidant Interactions\, and Acetylcholinesterase Inhibitory Ac tivities of Cranberry Polyphenol Fractions

\n

Advisor: Dr. Catherine Neto\, Chemistry & Biochemistry Dept.

\n

Committee Members: Dr. Shuow ei Cai\, Chemistry & Biochemistry Dept.\;  Dr. Brian Blanchette\, Chemist ry & Biochemistry Dept.

\n

ABSTRACT

\n

Cranberries (Vaccinium ma crocarpon) are polyphenol-rich fruits containing diverse bioactive compoun ds that possess antioxidant properties that can target a variety of biolog ical outcomes. Although synergistic interactions have been widely reported in multi-herb formulas\, little is known about the interactions among iso lated cranberry polyphenolic fractions. The present study aimed to investi gate the phytochemical composition\, antioxidant activity\, synergistic in teractions\, and acetylcholinesterase inhibitory potential of polyphenol-e nriched fractions isolated from Early Black (EB) and Mullica Queen (MQ) cr anberry cultivars. Crude cranberry extracts were fractionated using Diaion HP-20 and Sephadex LH-20 chromatography to isolate phytochemically distin ct fractions which were characterized by high-performance liquid chromatog raphy with diode array detection (HPLC-DAD)\, while selected proanthocyani din (PAC)-rich fractions were further characterized by matrix-assisted las er desorption-ionization-time-of-flight mass spectrometry (MALDI-TOF MS).< /p>\n

Antioxidant activities were evaluated using 2\,2-diphenyl-1-picryl hydrazyl (DPPH)\, 2\,2’-azionbis-(3-ethylbenzothiazoline-6-sulfonic acid ) (ABTS)\, and ferric reducing power (FRAP) assays. Fractions rich in flav onol glycosides and proanthocyanidins showed the most promising activity a nd were tested independently and as binary combinations (1:1\, 2:1\, and 1 :2) to evaluate their combined effects. These combinations were examined u sing both a single-concentration effect-based model and a dose-response Co mbination Index (CI) analysis to determine synergistic\, additive\, or ant agonistic interactions. The effect-based model identified synergistic beha vior between flavonol glycoside and PAC-rich fractions as well as between phenolic acid/ anthocyanin-rich fractions and PAC-rich fractions with rela tive reducing power (RRP) values ranging from 1.01-1.56\, whereas radical scavenging activity (RSA) of the mixtures were considered mainly antagonis tic with values ranging from 0.67-1.13. The second model instead suggested that most binary combinations exhibited mainly additive effects across al l antioxidant assays except for a 1:1 combination of MQ A I + M IV\, which showed moderate synergistic activity for scavenging ABTS (CI = 0.57). Sel ected fractions were also evaluated for acetylcholinesterase inhibitory ac tivity\, with the PAC-enriched fraction\, MQ A I\, exhibiting the greatest inhibitory activity against acetylcholinesterase with an IC50 value of 21 .1 mg/mL. Results of this study demonstrate that antioxidant interactions among isolated cranberry polyphenol fractions depends on phytochemical com position\, mixing ratio\, and mechanism tested. Understanding and exploiti ng these interactions may enhance their biological advantage while optimiz ing the bioactive compounds required to achieve desired effects.

\n

 

Event page: http s://www.umassd.edu/events/cms/8-4-26-defense-by-elena-de-pra-phytochemical -characterization-antioxidant-.php

DTSTAMP:20260717T225432 DTSTART;TZID=America/New_York:20260804T110000 DTEND;TZID=America/New_York:20260804T130000 LOCATION:VRB 210 SUMMARY;LANGUAGE=en-us:MS Thesis Defense by Elena De Pra, "Phytochemical Ch aracterization, Antioxidant Interactions, and Acetylcholinesterase Inhibit ory Activities of Cranberry Polyphenol Fractions" UID:1d7214a21c3d2aadb2d0c7d4b77e541b@www.umassd.edu END:VEVENT END:VCALENDAR