# US 9,434,710 B2 · Method for converting aloeresin A to aloesin

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- Number: US 9,434,710 B2
- Document ID: US9434710B2
- Status: Granted
- Kind: B2
- Application number: 11/909,063
- Filed: 2006-03-13
- Published: 2008-11-13
- Granted: 2016-09-06
- Earliest claimed: 2005-03-18
- Assignees: Csir, Bio/Chemtek
- Applicants: Lucia H. Steenkamp; Robin K. Mitra; Steven James Heggie; Vuyisile N. Phehane
- Inventors: Lucia H. Steenkamp; Robin K. Mitra; Steven James Heggie; Vuyisile N. Phehane
- Web page: https://patentgrep.com/patent/US9434710B2

## CPC

- C07D 311/22: with oxygen or sulfur atoms directly attached in position 4
- A61P 3/10: for hyperglycaemia, e.g. antidiabetics
- A61P 17/00: Drugs for dermatological disorders
- A61P 29/00: Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
- A61P 35/00: Antineoplastic agents
- A61P 39/06: Free radical scavengers or antioxidants
- A61P 43/00: Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
- C07D 407/04: directly linked by a ring-member-to-ring-member bond
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS

## Abstract

The invention provides a process for hydrolytically converting aloeresin A to aloesin by the following reaction: The amount of aloesin available for extraction from sap of aloe plants is thereby increased and the extraction and purification of the aloesin is also made easier and less costly. As aloesin is more commercially valuable than aloeresin A, the process also increases the commercial value of the sap or aloe bitters from the aloe plant. The process optionally also includes the step of separating the aloesin from the p-coumaric acid. Typical hydrolysis steps that are used in the process are acid hydrolysis, base hydrolysis and enzymatic hydrolysis. In the case of acid hydrolysis, the acid is any suitable organic or inorganic acid, such as hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid. In the case of enzymatic hydrolysis, the hydrolytic enzyme is typically an esterase, a lipase or a protease.

## Claims

### Claim 1

A method of extracting aloesin from aloe bitters comprising:
i.) subjecting aloe bitters obtained from an aloe plant to hydrolysis with an inorganic acid in a concentration of about 0.5N to about 10N, wherein said inorganic acid is selected from the group consisting of: hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, to provide hydrolyzed aloe bitters, and wherein said hydrolysis converts aloeresin A in the aloe bitters to aloesin and p-coumaric acid; and
ii.) extracting the aloesin from the hydrolyzed aloe bitters.

### Claim 2 (depends on 1)

The method of claim 1, wherein the aloe plant is Aloe ferox.

### Claim 3 (depends on 1)

The method of claim 1, wherein the inorganic acid is in a concentration of about 2N to about 5N.

### Claim 4 (depends on 1)

The method of claim 1, wherein said hydrolysis occurs in the presence of an organic solvent.

### Claim 5 (depends on 1)

The method of claim 1, wherein the organic solvent is ethanol or acetone.