Bioactives from NatureAndré Heeres, August 2018

Introduction

• André Heeres, Groningen, The Netherlands

• Syncom, Hanze University of Applied Sciences

• CRO in organic/medicinal chemistry

• 135 FTE (65% PhD)

• Pharmaceutical Industry

• Biobased activities (5-7 FTE)

• > 29.000 students

Content

• Natural Products in drug discovery

• Optimization/medicinal chemistry

• Lutein/Tagetes

Part I: Natural Products in Drug Disovery

Natural Products in Drug Discovery

• Natural Products Have an Outstanding Track Record

New chemical entities 1981-2014:

• Total: 1562

• 1/4 are natural products or natural product derived

Examples

General features of natural products

• Structural diversity and complexity

• More sp3 carbons and less nitrogen/halogens

• Chiral centers

Semi-synthesis

• Sometimes good is not good enough!

Optimization

The drug discovery process

• Total costs > 1.000.000.000 USD!!!! (billion)

Drug administration

• Preference for oral

administration

Requirements of drugs

• Question: What is required to become a successful

drug?

• Groups, 5-10 minutes

Requirements of drugs

“Farmaco-dynamics” (interaction)

• Activity for target receptor (“on-target”)

• Selectivity against other receptor (sub-)types

“Farmaco-kinetics” (ADME)

• (Administration, Distribution, Metabolism, Excretion)

• Bioavailability (transport, metabolic stability)

• Good duration of action (t 1/2)

Requirements of drugs (II)

“Farmaco-kinetics”

Good farmacokinetics require favourable physico-chemical properties….

• Water solubility > 20 mg/L

• “Compliance” to Lipinski and Veber “rules” (drug likeness)

MW HA/ HD clogP PSA RotB

Lipinski/Veber < 500 < 10/5 < 5 < 120 < 11

For CNS < 400 < 7/3 2 - 4 < 70 < 9

Present drugs 380 6/2 2.5 21 6

Requirements of drugs (III)

“Safety”

• No acute toxicity (e.g. cardiac [Herg], liver…)

• No long-term risks (DNA)

“Other”

• Chemical stability (heat, moisture…)

• Synthetic accessibility

• Patentability

- = Novelty (New Chemical Entity)

- + Inventivity (against existing patent claims)

- + Industrial application (therapeutic)

Requirements of drugs (IV)

Multi-factorial problem:

1. Improve all weak properties…..

2. …without destroying any strong properties

try to improve in cycles till the full

combination of properties is in

the acceptable range (or

fantastic)….

Modification of natural products (strategies)

• Simplifying structures

• Diminishing chiral centers

• Increasing activity or selectivity

• Increasing metabolic stability

• Improving physico-chemical

properties

Simplifying structures

• Decrease molecular size

• Eliminate unnecessary functional groups

• Halichondrin B (marine sponge, Halichondria okadai)

Erubilin

Breast cancer

FDA 2010

Diminish chiral centers

• Lovastatin (fungi; Pleurotus ostreatus)

Increase activity/selectivity

• Himbacine, Magnoleacea, Galbulimima baccata

Increase metabolic stability• Phlorizin (SGLT inhibitor) (bark of apple, strawberries, etc.)

• Aim: To increase metabolic stability and preferably increase activity

Improving physico-chemical properties

• Lavendustin A (potent in cell-free extracts (tyrosine kinase (epidermal growth factor

receptor))

• Aim: To decrease the solubility while balancing the (in vitro) activity

Inactive in cells Activity in cells

(mM range)

Activity in cells

(nM range)

in the clinic

Part II: Lutein from Tagetes

Tagetes in Northern Netherland

Bulb farming (tulips, lilies etc.)

• Use of marigolds (Tagetes spp.) for nematode suppression

(biological herbicide)

• 400 hectare (2017, growing at the 7 collaborating farms)

• Soil improvement (organics, etc.)

• “Beneficial for bees population”

Tagetes• Potential source of lutein, a high-value carotenoid

• Pharmaceutical, cosmetic (and nutraceutical) applications

• Ocular health

• Skin care (UV protection)

• Reduction of cancer

• Strengthening the immune system

• In 2010, lutein occupied a $233 million share of the worldwide carotenoid market (BCC

Research 2011).

• Lutein will be worth $309 million in 2018, a CAGR of 3.6%.

Lutein from Tagetes

Proces:

• Tagetes selection (herbicide + lutein)

• Harvesting flowers

• Drying and milling

• Extraction towards lutein esters

• Hydrolysis and purification

• Stabilization

• Conversion to other carotenes

Achievements

Tons/flowers tagetes per ha (2017, 6 x harvested)

Achievements

• Hybrid Tagetes

• 2016

- Planted middle May

- 6 x harvested

- Sunny conditions

• 2017

- Planted middle June (extremely wet)

- 3 x harvested

- Wet, cloudy weather

Lutein from tagetes in kg Drenthe 2016 Drenthe 2017

30-60 ton per hectare Bioresource Technol. 2015, 421-428 30000 33000 8400

drying Bioresource Technol. 2015, 421-428 4500 4950 1260

hexane extraction Sep. Sci. Tech. 2001, 265-271 450 495 126

hydrolysis and crystallisation Sep. Sci. Tech. 2001, 265-271 67,5 74,25 15,12

Achievements

• > 100 kg dried and milled flowers available

• 2017 > 5000 kg (wet) flowers (0.5 hectare)

• Extraction with heptane/supercritical CO2

(analysis in progress)

• Saponification and purification towards lutein >

50 g scale

• Increased lutein levels detected in eggs

chickens feeded with milled flowers of Tagetes

Optimization (aiming for)

• Alteration of lutein content – Increasing the dry weight lutein content of

marigold flowers.

• Alteration of visible properties of marigold – This includes aspects of

the flowers (more and/or larger flowers, flowers that all grow at the

same height) and of the stalk (flowers that are higher above the leaves

allowing for easier separation, a thicker stalk).

• Mechanical harvesting: e.g., Spanish Journal of Agricultural Research

2014 12(2): 329-337.

Towards higher value carotenes

Markets Zeaxanthin/Astaxanthin

Zeaxanthin

• Food/feed, cosmetics, pharma

• Anti-oxidant, macular degeneration

• Synthetic, extraction (marigold, paprika)

• Market 2020: USD 50 Million

Astaxanthin

• Food/feed, cosmetics, supplement

• Anti-oxidant, coloring properties

• Synthetic, extraction (plant, marine, yeast/microbes)

• Market 2020: USD 800 Million

Current synthesis

Zeaxanthin from Lutein (extracts)

Zeaxanthin:

• Extraction, chemical synthesis (3R, 3R’)

• From lutein

• Stereochemistry (3R, 3S’(meso))

• Epimerization needed in order to achieve market interest (3R, 3R’)

(3R,3R’)-Zeaxanthin from Lutein

(3R,3R’)-Zeaxanthin from epi-Lutein

Conclusions

• Natural products remain of interest for drug discovery, owing to their unique

structures

• Medicinal Chemistry is sometimes needed to transfer bioactive compounds

into real drugs.

• Tagetes is interesting source of carotenes!

Acknowledgements

Hanze University

• Dr. Patrick Uiterweerd

• Nanne Brattinga

• Jan Weever

• Dr. Doede Binnema

Syncom

• Dr. Jochem van Erpt

• Gerard Metselaar

• Sarah van Dijk

• Dr. Bernard van Vliet

• Dr. Jack den Hartog

• Dr. Ton Vries