Belgorod Summerschool

Bioactives from Nature

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)

Content

• Natural Products in drug discovery • Optimization/medicinal chemistry • Lutein/Tagetes

Natural Products in Drug Discovery

New chemical entities 1981-2014: • Total: 1562

General features of natural products

• More sp3 _{carbons and less nitrogen/halogens} • Chiral centers

Semi-synthesis

The drug discovery process

Drug administration

• Preference for oral administration

Requirements of drugs

•

Question: What is required to become a successful

drug?

Requirements of drugs

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

• Selectivity against other receptor (sub-)types “Farmaco-kinetics” (ADME)

• (Administration, Distribution, Metabolism, Excretion) • Bioavailability (transport, metabolic stability)

Requirements of drugs (II)

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)

• 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)

Requirements of drugs (IV)

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

Modification of natural products (strategies)

• Diminishing chiral centers

• Increasing activity or selectivity • Increasing metabolic stability • Improving physico-chemical

Simplifying structures

• Eliminate unnecessary functional groups

• Halichondrin B (marine sponge, Halichondria okadai)

Erubilin Breast cancer

Diminish chiral centers

Increase activity/selectivity

Increase metabolic stability

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

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

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.)

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 from Tagetes

• Tagetes selection (herbicide + lutein) • Harvesting flowers

• Drying and milling

• Extraction towards lutein esters • Hydrolysis and purification

• Stabilization

Achievements

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

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.

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

Zeaxanthin from Lutein (extracts)

Zeaxanthin:

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

• Stereochemistry (3R, 3S’(meso))

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.

Acknowledgements

• Dr. Jochem van Erpt

• Gerard Metselaar

• Sarah van Dijk

• Dr. Bernard van Vliet

• Dr. Jack den Hartog